The present study illustrates zooplankton dynamics in relation to environmental factors from the surrounding area of Tiaowei Island based on ten seasonal sampling cruises over three years. A total of 116 species of zooplankton were collected with a predominance of Copepoda (mainly consisting of Centropagidae, Oithonidae, Acartia, Labidocera and Paracalanus), accounting for 31.6 % of the total number of species. The diversity indices indicated a relatively high richness, abundance and evenness of zooplankton ranging from 2.794 to 4.012 on the Shannon–Wiener index for each cruise. More than 20 species of Cnidaria medusae are found as gelatinous organisms, which not only compete with fish but also potentially cause disasters. Significant seasonal variations were detected in both the zooplankton structure and environmental variables. NMDS illustrated a highly overlapping community structure in spring, autumn and winter, while the zooplankton composition in the summer was different from that of the other three seasons with a higher diversity index. Meanwhile, out of thirteen environmental parameters, eight varied significantly among seasons but there were no significant variations among stations. The biota–environmental relationship following a redundancy analysis revealed that water temperature, pH, salinity, dissolved oxygen and suspended particulate composition were the main environmental parameters, seasonally impacting the zooplankton communities. Planktonic larvae (such as nauplius larvae and branchyura zoea) and some zooplankton (including Corophium sinensis and Oithonasimilis) were significantly vulnerable to the dynamics of suspended particulate composition and water temperature.