Abstract: In order to study the effects of mussel culture on the forms and distribution of phosphorus in sediments, the spatial distribution and the bioavailability of various phosphorus in the sediments of Ma’an archipelago were analyzed by SMT phosphorus classification method. According to this method, Total phosphorus (TP), inorganic phosphorus (IP), organic phosphorus (OP), exchangeable phosphorus (Ex-P), iron aluminum bound phosphorus (Fe/Al-P) and calcium bound phosphorus (Ca-P) were extracted and determined, the organic phosphorus (OP) was the difference between TP and IP content. The results showed that the content of TP in the sediments of the aquaculture sea area of Ma’an archipelago ranged from 458.83 mg/kg to 507.60 mg/kg, with an average content of 477.14 mg/kg. Inorganic phosphorus was the predominate form of phosphorus, accounting for 78.97%～86.99% of TP. The content of phosphorus in each form of IP was in the order of Fe/Al-P>Ca-P>Ex-P, which accounted for 29.98%、27.50% and 8.35% in TP, respectively. Bioavailable phosphorus (BAP) can be used to judge the endogenous release capacity of phosphorus in sediments. Its content was 172.34～266.86 mg/kg, with an average content of 231.33 mg/kg, accounting for 47.55% of TP. The correlation between phosphorus fraction and particle size showed that both Fe/Al-P and BAP showed a highly significant positive correlation with fine-grain size. In addition, the spatial distribution of various forms of phosphorus in the culture sea area generally showed the trend of mussel culture core area > adjacent area > potential impact area > control area, indicating that mussel culture activities had a certain acting sphere on the phosphorus in sediments of the adjacent sea area, and the main impact range was estimated to be about 1 km.