By the method of comparative analysis, the author makes the disparity in every aspect of agriculture between china and developed countries clear, and analyses relationship between modernization of agriculture and the whole economy. Estimation that the lag of level of agricultural modernization between China and developed countries is about 80 years is made. To quicken the realization of agricultural modernization in China, developing agricultural science and technology, improving the level of mechanization, advancing agricultural industrialization, reforming the patterns of agricultural operation organizations, promoting the development of agriculture for export and perfecting legal system were put forward as policy suggestions.