Combing ancient literatures like lü Shi Chun Qiu and the unearthed iron plows, this paper holds that iron colter first appeared in Chun Qiu Period, and the popularization of Iron Plow Technology was in Han Dynasty.The popularization of Iron Plow Technology and the continuous progress of iron plow in making material and shape provided the necessary tool and power equipment for comprehensively realizing of Chin-Han Dynasties' agricultural technology, such as deep plough and careful cultivation, which made China's ancient agricultural technology produce a qualitative leap.