Abstract: To understand the basics of ecological environment in Bali Lake, the large macrobenthos of Bali Lake were systematically investigated in spring and autumn of 2020. The results showed that the dominant species of Bali Lake were Aulodrilus sp., Limnodrilus sp. and Tanypus sp., which are all organic matter tolerant. The density in autumn was higher than that in spring, while the biomass in spring was higher than that in autumn, but the differences were not significant. In spring and autumn, the Shannon-Wiener diversity index separately was 2.68 (mild pollution) and 1.42 (moderate pollution), the biotic index was 7.56 (mild pollution) and 7.11 (mild pollution), the BMWP index was 12.5 (moderate pollution) and 7.1 (severe pollution). The Shannon-Wiener diversity index was 2.05 (mild pollution), the biotic index was 7.34 (mild pollution), the BMWP index was 9.8 (severe pollution) of Bali Lake all year round. It is indicated that Bali Lake was in a state of mild to severe pollution. Redundancy analysis showed that NO3-N, DO and NH4-N significantly affected the distribution and structure of the macrobenthos community. The results can provide theoretical basis and data support for water ecological protection in Baili Lake.