Abstract: This paper compared agricultures in developed countries and in China, found the difference, and pointed out that it is indispensable to develop agricultural engineering in order to accomplish China's agricultural development strategic task of the next period — optimizing the agriculture and rural economy structure of China, improving the efficiency and benefit of agriculture, and raising farmer's income. With facts, this paper set forth that agricultural engineering development has tremendous effect on the following seven aspects: improving the quality of agricultural products, raising the efficiency and benifit of plant industry, accelerating the development of animal husbandry, advancing agro product processing, optimizing agricultural distribution, readjusting rural employment structure, promoting the development of rural industry and small towns, industrializing agriculture, and enrolling the international challenge.