Abstract: This article is based on the survey data of surface frame trawl in winter (January), spring (April), summer (August) and autumn (November) of 2023, the composition of the fish community in Weizhou island, Guangxi, and its relationship with environmental impact factors were investigated.The relationship between the density of fish resources and the population of Balaenoptera edeni was also explored. The results showed that a total of 72 species of 51 genera and 27 families in 11 orders were identified in fishes community. The main orders were Perciformes, Clupeiformes, and Beloniformes. Both fish tail number and biomass resource density were highest in summer (226.91×10³ ind/km², 1476.65 kg/km²), followed by winter (55.18×10³ ind/km², 544.21 kg/km²), and lowest in spring (10.95×10³ ind/km², 387.77 kg/km²). Redundancy analysis showed that water temperature, nutrients, and bait food zooplankton were the important ecological factors for the seasonal change of fish resources in Weizhou island, Guangxi. Thryssa dussumieri was the first dominant species in all four seasons, and its relative importance index was highest in spring (13626.60) and second highest in winter (12209.23). At the same time this species was the main feeding baitfish of B. edeni. Correlation analysis showed that the B. edeni population was significantly affected by the density of fish, especiall Thryssa dussumieri, which is the main food for B. edeni in Weizhou island. The results of this study can provide support for the protection and management of fish resources in Weizhou island, Guangxi, as well as for the research and protection of the population and habitat ecosystem of B. edeni.