Abstract: The study took Sancha Lake in Chengdu as the research area. Through comprehensive surveys of its physical habitat, physicochemical water characteristics, and aquatic biological indicators, a health assessment index system for the Sancha Lake aquatic ecosystem was constructed using the comprehensive index method, and the health status of the ecosystem was evaluated. The results indicated that the overall physical habitat condition of Sancha Lake was good. Specifically, the tail area of the reservoir exhibits moderate habitat quality, while the water inlet, central lake area, and outlet areas remained in good condition. In terms of physicochemical water characteristics, the water quality generally met the Class III surface water standards. During the high-flow period, slight exceedances of the dichromate index (COD_cr) and total phosphorus (TP) content were observed in some surveyed areas, with an exceedance rate of 60%. The overall trophic status was good, with no risk of eutrophication. The evaluation results of the Shannon-Wiener diversity index for various aquatic organisms showed differences. Benthic macroinvertebrates (14 species) were rated as poor; periphytic algae (29 species) were rated as good; zooplankton (dominated by rotifers and copepods) and phytoplankton (21 genera) were both rated as moderate; and the aquatic plant community had not yet formed a significant scale. The comprehensive assessment revealed that the health status of the Sancha Lake aquatic ecosystem was moderately low, with aquatic organisms being the primary limiting factor for overall ecosystem health. Although multiple assessment indicators showed improving trends, the overall quality still requires enhancement. Future efforts should strengthen ecological management of water quantity regulation and improve the stability of aquatic habitats.