在美國，出洋預習班的同學們，目睹北美西歐科學 技術的巨大成就，對機器、火車、輪船及電訊制造業的迅速發展贊嘆不已。有的同學由此對中國的前途產生悲觀情緒，詹天佑卻懷著堅定的信念說：“今後，中國也要有火車、輪船。”他懷著為祖國富強而發奮學習的信念，刻苦學習，於1867年以優異的成績畢業於紐海文中學業。同年五月考入耶魯大學土木工程系，專攻鐵路工程。在大學的四年中，詹天佑刻苦學習，以突出成績在畢業考試中名列第壹。1881年，在壹百二十名回國的中國留學生中，獲得學位的只有兩人，詹天佑就是其中的壹個。
回國後，詹天佑滿腔熱忱地準備把所學本領貢獻給祖國的鐵路事業。但是，清政府洋務派官員迷信外國，在修築鐵路時壹味依靠洋人，竟不顧詹天佑的專業特長，把他差遣到福建水師學堂學駕駛海船。1882年11月又被派往旗艦“揚武”號擔任駕駛官，指揮操練。1883年，中法戰爭爆發，第二年，蓄謀已久的法國艦隊陸續進入閩江，蠢蠢欲動。可是主管福建水師的投降派船政大臣何如璋卻不聞不問，甚至下令：“不準先行開炮，違者雖勝亦斬！”這時，詹天佑便私下對“揚武”號管帶（艦長）張成說：“法國兵船來了很多，居心叵測。雖然我們接到命令，不準先行開炮，但我們決不能不預先防備。”由於詹天佑的告誡，“揚武”號十分警惕，作好了戰鬥準備。當法國艦隊發起突然襲擊時，詹天佑冒著猛烈的炮火，沈著機智地指揮“揚武”號左來右往；避開敵方炮火，抓住戰機用尾炮擊中法國指揮艦“伏爾他”號，使法國海軍遠征司令孤拔險些喪命。對這場海戰，上海英商創辦的《字林西報》在報道中也不得不驚異地贊嘆：“西方人士料不到中國人會這樣勇敢力戰。‘揚武’號兵艦上的五個學生，以詹天佑的表現最為勇敢。他臨大敵而毫無懼色，並且在生死存亡的緊要關頭還能鎮定如常，鼓足勇氣，在水中救起多人……”
從戰後到1888年，詹天佑兒經周折，轉入中國鐵路公司，擔任工程師，這是他獻身中國鐵路事業的開始。
剛上任不久，詹天佑就遇到了壹次考驗。當時從天津到山海關的津榆鐵路修到灤河，要造壹座橫跨灤河的鐵路橋。灤河河床泥沙很深，又遇到水漲急流。鐵橋開始由號稱世界第壹流的英國工程師擔任設計，但失敗了；後來請日本工程師衽實行包工，也不頂用，最後讓德國工程師出馬，不久也敗下陣來。詹天佑要求由中國人自己來搞，負責工程的英國人在走投無路的情況下，只得同意詹天佑來試試。
詹天佑是壹個認真踏實的人，他分析總結了三個外國工程師失敗的原因後，身著工作衣與工人壹起實地調查，（P116）密測量。夜晚，借著幽暗的油燈，又仔細研究灤河河床的地質構造，反復分析比較，最後才確定橋墩的位置，並且大膽決定采用新方法——“壓氣沈箱法”來進行橋墩的施工。詹天佑果然成功了灤河大橋建成了。這件事震驚了世界：壹個中國工程師居然解決了三個外國工程師無法完成的大難題。
詹天佑初戰告捷後，立刻遇到了更為嚴峻的考驗。1905年，清政府決定興建我國第壹條鐵路京張鐵路（北京至張家口）。英俄都想插手，由於中國人民的強烈反對，他們的企圖沒能得逞。英俄使臣以威脅的口吻說：“如果京張鐵路由中國工程師自己建造，那麽與英俄兩國無關。”他們原以為這麽壹來，中國就無法建造這條鐵路了。在這關鍵時刻，詹天佑毫不猶豫地接下了這個艱巨的任務，全權負責京張鐵路的修築。消息傳來，壹些帝國主義分子及英國報刊挖苦說：“中國能夠修築這條鐵路的工程師還在娘胎裏沒出世呢！中國人想不靠外國人自己修鐵路，就算不是夢想，至少也得五十年。”他們甚至攻擊詹天佑擔任總辦兼總工程師是“狂妄自大”、“不自量力”。詹天佑頂著壓力，堅持不任用壹個外國工程師，並表示：“中國地大物博，而於壹路之工必須借重外人，我以為恥！”“中國已經醒過來了，中國人要用自己的工程師和自己的錢來建築鐵路。”
1905年8月，京張鐵路正式開工，緊張的勘探、選線工作開始了。詹天佑帶著測量隊，身背儀器，日夜奔波在崎嶇的山嶺上。壹天傍晚，猛烈的西北風卷著沙石在八達嶺壹帶呼嘯怒吼，刮得人睜不開眼睛，測量隊急著結束工作，填個測得的數字，就從巖壁上爬下來。詹天佑接過本子，壹邊翻看填寫的數字，壹邊疑惑地問：“數據準確嗎”？“差不多”，測量隊員回答說。詹天佑嚴肅地說：“技術的第壹個要求是精密，不能有壹點模糊和輕率，‘大概’、‘差不多’這類說法不應該出於工程人員之口。”接著，他背起儀器，冒著風沙，重新吃力地攀到巖壁上，認真地復勘了壹遍，修正了壹個誤差。當他下來時，嘴唇也凍青了。
不久，勘探和施工進入最困難的階段。在八達嶺、青龍橋壹帶，山巒重叠，陡壁懸巖，要開四條隧道，其中最長的達壹千多米。詹天佑經過精確測量計算，決定采取分段施工法：從山的南北兩端同時對鑿，並在山的中段開壹口大井，在井中再向南北兩端對鑿。這樣既保證了施工質量，又加快了工程進度。鑿洞時，大量的石塊全靠人工壹鍬鍬地挖，湧出的泉水要壹擔擔地挑出來，身為總工程師的詹天佑毫無架子，與工人同挖石，同挑水，壹身汙泥壹臉汗。他還鼓舞大家說：“京張鐵路是我們用自己的人、自己的錢修建的第壹條鐵路，全世界的眼睛都在望著我們，必須成功！”“無論成功或失敗，決不是我們自己的成功和失敗，而是我們國家的成功和失敗！”
為了克服陡坡行車的困難，保證火車安全爬上八達嶺，詹天佑獨具匠心，創造性地運用“折返線”原理，在山多坡陡的青龍橋地段設計了壹段人字形線路，從而減少了隧道的開挖，降低了坡度。列車開到這裏，配合兩臺大馬力機車，壹拉壹推，保證列車安全上坡。
詹天佑對全線工程曾提出“花錢少，質量好，完工快”三項要求。京張鐵路經過工人們幾處奮鬥，終於在1909年9月全線通車。原計劃六年完成，結果只用了四年就提前完工，工程費用只及外國人估價的五分之壹。壹些歐美工程師乘車參觀後嘖嘖稱道，贊譽詹天佑了不起。但詹天佑卻謙虛地說：“這是京張鐵路壹萬多員工的力量，不是我個人的功勞，光榮是應該屬於大家的。”
京張鐵路建成後，詹天佑又繼任了粵漢鐵路督辦兼總工程師。這時，美國決定授予他工科博士學位，要他親自去美國參加授銜儀式。為了全力參加祖國鐵路建設，他放棄了這壹榮譽。
辛亥革命後，詹天佑為了振興鐵路事業，和同行了起成立中華工程學會，並被推為會長。這期間，他對青年工程技術人員的培養傾註了大量心血，他除了以自己的行為作出榜樣外，還勉勵青年“精研學術，以資發明”，要求他們“勿屈己徇人，勿沽名而釣譽。以誠接物，毋挾褊私，圭璧束身，以為範例。”
詹天佑從事鐵路事業三十多年，幾乎和當時我國的每壹條鐵路都有不同程度的關系。到晚年，因積勞成疾，不幸於1919年病逝。周恩來同誌曾高度評價詹天佑的功績，說他是“中國人的光榮”。
詹天佑英文簡介
Tianyou (1861-1919), wife and children - and word-flows and native Anhui inspecting (currently under Jiangxi), Qianlong 25 years (1760), grandfather of tea with family members to Guangzhou operating business. Jiaqing 21 years (1816), grandfather moved outside 12 just West, the South China Sea 25 years naturalization counties (12 of the South China Sea just at the time of arrest). Represented parents live in just 12. Represented was born in Guangzhou. Rule together 11 years (1872), as young as 12 years old represented the first successful U.S.-selected government study, with his Hong traveling abroad. 1878 (1878) entered the United States Yale University Civil Engineering Department, the study projects, outstanding. Guangxu seven years after the return, sent ships Councils Fuzhou Navy ships driving school to learn, by five goods military exploit. The following year graduated in Jan force of warships sent. Guangxu decade of Fuzhou ship Councils school teacher for teaching seriously, by the Qing government Dingdai five goods. In autumn, the Governor should be sold Zhangzhidong request, to the Guangdong Province Guangdong Whampoa real learning Museum teacher. After a study hall instead learned Museum, surface inspection division. Represented continuation, and in the design and construction of Battery mapping coastal charts. Guangxu 14 years to Tianjin-China Railway Engineering Corporation Gang Division (now the engineers. The same below), in the construction of Jingu Railway. Later in the construction of Tianjin elm Railway, the use of "pressure gas caisson method" piling, the successful completion of the Great River Bridge Luan River bridge foundation works to address the unresolved problems of foreign engineers. Guangxu 20 years been absorbed in the British Civil Engineering Institute. Thereafter has engaged in Tianjin Lo, Jinzhou, Ping, sweet wine such as railway construction. Guangxu 28 years, appointed a new independent Yi railway projects for my own preparations for Beijing Zhang railway done. Guangxu She recommended to the Department of Business, a 4-foot 8-inch National Unity (1.435 m) standards track uniform engineering standards, promote the use of automatic coupling to our own design and lay a sound foundation for the construction of the railway. This year, he was appointed to the Department, the Department of Road Works Members and mail consultants, and elected to Shanghai, the European Institute of Architects Royal Engineers. In the same year he was transferred to Beijing Zhang, Chief Engineer of the railway will run, the total run, the construction of Beijing Zhang Railway. According to the terrain will be represented in Shanyao tracks running "person" font, circuitous travel, followed and, in order to meet the Tsing Lung Bridge, the route than originally planned to reduce by half. Railway line in Beijing Zhang construction process, the use of blasting France, launched Block 4 Tunnel. Badaling tunnels which span 1,091 metres, drilling, construction of a straight wells France, accelerated progress cave had no little difference to Jing Zhang railway built two years earlier, in Xuantong Period 145,000 (1909) officially opened in August. British chief engineer Kinda Cox also agreed with the "music." Jing Zhang of China Railway built a milestone in the development of modern science and technology, represented the first railway to train engineers for the construction of a well-developed railway and railway traffic management, road maintenance, motorcycles, cable, and a patrol. Xuantong Period 2002 (1910), represented by the court in awarding engineering Scholars first. Xuantong Period spring back to the Guangzhou office of three years 粵漢 Canton Railway Corporation to run Premier (general manager) and the total project Division. In May leading Guangdong Lu company Lo authorities against court to "state" for the right to sell foreign player Lu. Wuchang Uprising, leading Yue - Han Railroad personnel to all positions and ensure that trains will operate in support of the Revolution of 1911. The first (1912) in May represented in the sand Station (provincial Yue - Han Railroad Company headquarters) to Dr. Sun Yat-sen inspections. July was appointed Yue - Han Railroad will be running. In December Renhan Guangdong and Sichuan Road will be done to help manage and competent engineering services. In Guangzhou tenure, the creation of a multidisciplinary academic groups Guangdong China engineer, was elected the first president. 1913, the initiative will be engineers Guangdong China, the Shanghai Institute, the Shanghai Road will be merged my masonic 3 in the establishment of China Hankow engineers will be elected the first president. Granted by the government in 1914 and was promoted to second class Jiahe Zhang Han Guangdong and Sichuan for rail handling, after his election as Member of the British railway track. 1919, on behalf of Northeast China to attend the joint supervision of the Far East Railway International Conference strongly defend national sovereignty. Represented write a "Railway terminology table", "Wa Ying workers learn new vocabulary," and has edited the "Jing Zhang railway standards," and "Jing Zhang Railway Discipline slightly." 24 April 1919 at Hankow under death behind Beijing. By the PRC Ministry of Railways in 1982 held a grand ceremony of the Tsing Lung Bridge Juyongguan have left the station.