Leizhou Bay, located on the eastern side of Leizhou Peninsula in Guangdong province, is the primary habitat of Chinese white dolphin (), besides being a reserve for juvenile fish and shrimp. However, the ecological state of this coastal ecosystem remains largely unknown. To understand the fish community structure and its physical drivers in Leizhou Bay, seasonal bottom trawl along with environment monitoring surveys were conducted from 2016 to 2017. The relationships of fish community structure with environmental factors were analyzed using K-means cluster analysis, similarity percentage analysis, and redundancy analysis. These analyses led to the identification of 256 fish species, comprising mainly demersal fish and warm-water fish. The study sites for each season could be divided into two groups:group I, with water depth of less than 10 m, and group Ⅱ, with water depth between 10 m and 20 m. Group I showed an average similarity of 38.48%-47.44% across seasons in terms of fish community structure (which was shown as matrixes of sites by species biomass). Three species, Plotosus lineatus contributed greatly to the average similarity within Group I in summer, fall and winter. Furthermore, Group Ⅱ showed an average similarity of 41.38%-52.59% across seasons. The contributed mostly to the average similarity within Group Ⅱ in spring, summer and winter. The average dissimilarity between group I and group Ⅱ in seasons was 57.74%-76.25%. Six ecological factors, i.e. depth, dissolved oxygen, water temperature, salinity, pH, and chlorophyll a, explained 41.76%-47.11% of variation in fish biomass, with depth being the dominant environmental factor affecting fish community structure in each season. Moreover, the fish species richness in Leizhou Bay was obviously higher than in other bays of China. This study provides preliminary data on fish community structure and its relationship with environmental factors in Leizhou Bay, and provides clues for stocking enhancement in the waters.