Abstract: Research and conservation of fish spawning grounds are important for restoring fish biodiversity. This study combined remote sensing and hydrodynamic model to identify the potential spawning grounds of phytophilic fish in Poyang Lake from 2000 to 2020, and analyze their spatial and temporal variation characteristics to investigate the protection efficiency of the current spawning ground natural reserve. The results showed that the area of potential spawning grounds has been increasing in the past 20 years, and expanded from the lake shore to the center of the lake. The average area of potential spawning grounds before and after 2005 is 519.97 and 694.42 km², respectively, the area and spatial distribution of spawning grounds have changed significantly. After 2005, the spawning grounds expanded to the center of the lake, and a large area of continuous potential spawning grounds appeared in Duchang. The current nature reserve contains 17.75% of potential spawning grounds on average, and the sub-lakes contains 34.73% of potential spawning grounds on average. The distribution of potential spawning grounds can further guide the optimization of the reserve and the field survey in Poyang Lake, and the method used in the study is also applicable to the identification of potential spawning grounds of phytophilic fish in other regions.