Abstract: This study investigates the impact of heavy metal pollution on biofilm communities in the Anning River, Sichuan Province, aiming to provide a scientific basis for water pollution control and ecological protection. By analyzing indicators such as chlorophyll-a, extracellular enzyme activity, and polysaccharide content in biofilm communities at various sampling points, the effects of Cd and Pb in different media on biofilm communities were explored to reveal their response relationships with environmental factors. The results indicate that: Cd content in water and suspended solids was significantly higher at sites S3 and S4 compared to other sampling points, with the lowest concentration found at S12. In sediment and biofilms, the highest Cd content was observed at S14, while the lowest levels were found at S6 and S12, respectively. Pb content in all four media was higher at S3 and S4 than at other points, with the lowest concentration at S12. Specifically, Pb concentrations at S3 and S4 were 0.348 mg/L and 0.308 mg/L, respectively, exceeding the Class III water quality standard limits. Cd content in sediment exceeded the soil background values of Sichuan Province at all sites, with the highest level at S14 surpassing the background value by 23.8 times. Pb levels also exceeded background values at all sites except S12, with the highest exceedance at S3(75.1 times the background value). The distribution pattern of Cd and Pb concentrations across the four media followed the order: biofilm > suspended solids > sediment > water. Both Cd and Pb exhibited negative correlations with chlorophyll-a(Chla) and glucose(GLU). Redundancy analysis(RDA) revealed that heavy metals Cd and Pb in the water body had a significant influence on biofilm communities.