Through analysis on water quality, planktonic organism, fish resources, and fish species diversity in Yantan water area, this paper evaluated current situation of quality of fishery ecological environment in Yantan water area. The survey recorded all 52365 fishes and 1410.2 kg catches obtained by fishermen in half a year, and more than 98% catches are small fishes. The Shannon-Weiner diversity index of Yantan water area is 0.162, Wilhm improvement index is 1.814, DG-F index is 0.083, and the index of fish species diversity is far lower than other water areas. The average quantity per unit of phytoplankton is 1.0134 million ind./L, and the average quantity per unit of organisms is 1.1151 mg/L. The average quantity per unit of zooplankton is 459.6 ind./L, and the average quantity per unit of organisms is 0.6422 mg/L. Evaluation results indicate that water quality and planktonic organism in Yantan water area are basically normal, but fish resources are increasingly exhausted, fish resource composition is not reasonable, and fish species diversity is extremely low. From the perspective of biomanipulation, it is required to restore fishery ecological environment of reservoir area through restoring normal composition of aquatic organisms.