Abstract: 【Objective】This study analyzed the species composition,community structure,biodiversity and environmental factors of macrobenthos in the northern waters of Beibu Gulf,providing data support for ecological monitoring,environmental assessment,and protection of macrobenthos diversity in the northern waters of Beibu Gulf,as well as providing scientific basis for the sustainable development and utilization of marine resources.【Method】Conducted macrobenthos sampling at a total of 20 survey stations in the northern waters of Beibu Gulf from October to November 2020 (autumn) and April to May 2021 (spring),zoobenthos abundance,biomass,dominance (Y),and species replacement rates were counted,and Shannon-Wiener diversity index (H'),Margalef richness index (D) and Pielou evenness index (J') were calculated.The dominant species in delimiting communities were identified by similarity percentage (SIMPER),the disturbance of macrobenthos communities was analyzed by ABC curves (abundance/biomass),and Pearson correlation between environmental factors and the diversity of macrobenthos (H',J'and D) was analyzed using SPSS 24.0.【Result】The spring survey identified 50 species of macrobenthos which belonged to 9 phyla,with 12 dominant species;the autumn survey identified 40 species which belonged to 5 phyla,with 10 dominant species;the dominant species existed both in spring and autumn included Amphiolus lucidus,Tylorrhynchus heterochaetus and Branchiostoma japonicum.The average abundance of macrobenthos in spring was 143.11 ind/m²,and in autumn was 186.38 ind/m².The average biomass in spring was 18.92 g/m²,and in autumn was 24.15 g/m²;macrobenthos diversity in spring was greatly higher than autumn,presented as spring H'(1.566)>autumn H'(1.126),spring J'(0.780)>autumn J'(0.613),and spring D(0.694)>autumn D(0.548).The community structure of macrobenthos in the northern waters of Beibu Gulf could be divided into5 groups in spring and 4 groups in autumn,with the characteristic species presented in both seasons being A.lucidus and B.japonicum.The result of Pearson correlation analysis showed that there was no significant correlation (P>0.05) between H',J'and D of macrobenthos and environmental factors in spring,and combined with the ABC curve analysis,it could be seen that the macrobenthos community in the northern waters of Beibu Gulf was less disturbed in spring;in autumn,H'was significantly positively correlated with dissolved oxygen (P<0.05,same below) and negatively correlated with water temperature,nitrate and dissolved inorganic nitrogen;J'was significantly positively correlated with dissolved oxygen and pH,and negatively correlated with phosphate,nitrate and dissolved inorganic nitrogen;and D was extremely significantly positively correlated with dissolved oxygen (P<0.01) and significantly negatively correlated with water temperature,phosphate,nitrate and dissolved inorganic nitrogen.【Conclusion】There may be moderate pollution or disturbance in the northern waters of Beibu Gulf,and the biological community structure in this sea area is less stable in autumn;environmental factors including water temperature,dissolved oxygen,phosphate,nitrate,and dissolved inorganic nitrogen are the main factors affecting the macrobenthos community in autumn.That means controlling nitrogen and phosphorus input is an important measure to maintain the ecological balance of the waters of Beibu Gulf.