Based on China's micro data from 2012 to 2020, this article takes water resources enterprises as the research objects, and conducts an empirical analysis of the relationship between R&D investments and enterprise growth. This article measures the growth of an enterprise with a comprehensive factor score. Moreover, in order to eliminate the endogenous problems and intertemporal effects of the R&D investments of enterprises, this article uses System Generalized Moment Estimation (SYS-GMM) to conduct an empirical analysis of the relationship between R&D investments and enterprise growth. In addition, this article also examines the role of government R&D subsidies in regulating this relationship. The results show that there is a U-shaped relationship between the growth of water resources enterprises and their R&D investments. Besides, government R&D subsidies can adjust the relationship between R&D investments and enterprise growth, and make the U-shaped curve slope of the relationship between the two more gentle.