Abstract: The construction of ecological corridor in lakeside zone is a a novel approach to restoring the ecology of the lakeside, but little attention has been paid to the effects of corridor on the distribution and diversity of aquatic communities in this zone. In this study, we investigated the changes in fish community characteristics in different types of bays (S-type and L-type) before and after the construction of the ecological corridor in Erhai Lake. The results showed that: (1) The construction of ecological corridor caused decrease of fish dominance in S-type bays, but an increase in L-type. (2) The fish diversity index in L-type increased significantly after construction, with the H′ showing a significant difference compared to before (P<0.05), however, the diversity index decreased in S-type. (3) The fish density decreased in S-type, but the biomass increased due to an increase in the abundance of medium and large-sized fish, while the abundance of small-sized fish increased in L-type. The fish abundance biomass comparison curve showed that the S-type was a moderate disturbance after construction, while, the disturbance of L-type was mild and the fish community structure was more stable. (4) RDA analysis showed that water transparency, pH and water depth were the main environmental factors affecting fish biomass in both S-type and L-type bays, and silver carp was the dominant fish. In conclusion, the construction of ecological corridor has a significant impact on the structure of fish community, particularly in S-type where it leads to a rapid change in fish composition community. Therefore, it is suggested that ecological corridor construction should focus on the transformation of L-type. This study provides a theoretical basis for the protection of fish diversity and habitat restoration.