By using Cai Fang’s method of dividing China’s economic development stages, the changes of factor structure, conflicts of elements, characteristics of the development of agricultural mechanization and its developments stage attribution have been analyzed. The study shows that in the Malthusian trap development stage, large agricultural labor force silted up in the countryside; the capital element was insufficient; the agricultural mechanization developed very slowly. In Lewis dual economic development stage, the level of agricultural mechanization improved with the increase of factor flow radius. During the Lewis transition period, there was a shortage of elements and the development speed of agricultural mechanization slowed down. In neoclassical economic development stage, factor market competition spurred agricultural mechanization level to improve quickly. Therefore, the deceleration of development of agricultural mechanization is the periodic characteristic and the inevitable result in the process of economic development. As a result, in the framework of this continuous spectrum panorama, it is necessary to regulate the circulation of land, to carry out land improvement projects, to standardize the agricultural machinery subsidy process, to improve the level of agricultural machinery manufacturing, and to accelerate the integration of three industries development in rural areas so as to realize the modernization of agricultural machinery.