To identify the composition and diversity of fish larvae and juveniles in the coastal waters of theMinnan fishing grounds, the species composition and quantity distribution of fish larvae and juveniles, as well asthe relationship between the hydrological characteristics of the waters of the fishing grounds in Minnan and thedistribution of fish larvae and juveniles, were studied. Ecological research data were obtained for the larvae andjuveniles studied in four voyages carried out in May 2022 (spring), November 2022 (autumn), February 2023(winter), and July 2023 (summer). It was found that: (1) a total of 1114 fish larvae and juveniles were collected on4 voyages, belonging to 9 orders, 40 families, and 87 species, of which the number of Perciformes was the largest,accounting for 65.26% of the total number of fish larvae and juveniles in the study area. The abundance of fishlarvae and juveniles and the number of species were the highest in summer, and the abundance of fish larvae andjuveniles and the number of species were the lowest in autumn. The dominant species in each quarter were obvious,and there were no common dominant species. (2) There are significant differences in the composition of the fishlarvae and juvenile clusters in the Minnan fishing grounds. The species replacement rates in the four seasons were88.46%, 98.15%, 100.00%, and 92.11%, respectively. The results of the diversity analysis show that the richnessindex (D) and the Shannon-Wiener diversity index (H') were the highest in the summer, but the Pielou evennessindex (J') was highest in the winter. (3) Analysis of the similarity of the assemblages of fish larvae and juvenilesshowed that the assemblages of fish larvae and juveniles in spring, summer, and winter were obvious. Duringspring, fish larvae and juveniles can be divided into two groups: nearshore and offshore. In summer and winter, thefish larvae and juveniles can be divided into three groups: the nearshore group, the offshore group I, and theoffshore group II. (4) Analysis of the correlation between spatial and temporal distribution and environmentalfactors of the fish larvae and juveniles revealed that the changes in salinity between different stations and thetemperature changes between seasons are the main factors that affect spatial and temporal distribution. The resultsof this study provide a scientific basis for studying the replenishment mechanism of fishery resources in theMinnan fishing grounds and formulating measures for the conservation and management of fishery resources.