The imbalanced development of China’s agricultural modernization among different regions is very disadvantageous to the comprehensive realization of China’s agricultural modernization. Therefore, it is of great significance for the coordinated development of China’s agricultural modernization to explore and study the spatiotemporal characteristics and regional imbalance of China’s agricultural modernization. In this paper, from the modernization of agricultural production, agricultural modernization management, quality of agricultural modernization, rural social economic modernization, the modernization of agriculture ecological environment five dimensions to build agricultural modernization evaluation index system, by using variation coefficient method, determining the weight to the level of agricultural modernization in China in 2004-2017 to measure and evaluation, analysis of the characteristics of space and time and the restricting factors of agricultural modernization in China. The research shows that: (1) From 2004 to 2017, the level of agricultural modernization in China and various regions has been gradually improved, but the difference between the level of development and the speed of improvement is obvious. (2) The contribution rate and driving effect of each subsystem on the overall development of agricultural modernization in different regions are significantly different at different stages, resulting in the unbalanced development of agricultural modernization in each region; (3) For the development of the regional agricultural modernization of the main factors in 2004-2017: the eastern region to the low level of modernization of agricultural production subsystem development, the central region the low level of development, modernization of agriculture ecological environment subsystem in the western region agricultural modernization quality benefit subsystem development level is low, the rural social economic modernization in northeast China subsystem development level is low. It can be seen from the temporal and spatial characteristics of China’s agricultural modernization development: from 2004 to 2017, the development level of agricultural modernization has been gradually improved, but there are obvious regional differences in the development level of agricultural modernization, leading to different regional constraints affecting the development of agricultural modernization. Finally, the paper puts forward some policy Suggestions to realize the balanced development of agricultural modernization.