The report on the 18th session of the National People’s Congress first proposed that we should promote the simultaneous development of industrialization, informatization, urbanization and agricultural modernization. “Four New Modernizations” are the basic contents of China’s modernization. They influence each other, cooperate with each other, accelerate with each other and jointly promote social and economic development. This paper summarized an interaction model based on the analysis of interactive mechanism among industrialization, informatization, urbanization and agricultural modernization. Meanwhile, we measured and evaluated their interactive relationship by using Entropy Method and Granger Causality Test Method. Results show that there exists positive interaction between China's industrialization & informatization, industrialization &urbanization, urbanization & informatization, urbanization & agricultural modernization, each couple can influence each other while the industrialization and agriculture modernization, informatization and agricultural modernization failed to achieve the mutual interaction.