Potassium persulfate ultraviolet spectrophotometer was used to determine the total phosphorus(TP) and the phosphorus form was extracted by the SMT(Standard Measurement Test) method in the sediments of northern Hangzhou Bay, the organic P (OP) content was the difference between TP and inorganic phosphorus(IP) content, and the spatial distribution of phosphorus forms was also studied. The results showed: TP in the sediments ranged from 722.25 μg/g to 874.49 μg/g which increased gradually along the coast, 63% of TP was IP, and Calcium-bound phosphorus(Ca-P), Organic phosphorus(OP), Fe-Al-bound(Fe/Al-P) phosphorus and Exchangeable phosphorus(Ex-P) were the main forms of phosphorus.The content of Ca-P decreased from south to north in northern Hangzhou Bay, while the content of Fe/Al-P was higher in northern Hangzhou Bay and decreased gradually as it extended to the open sea; The spatial distribution of Ex-P was similar to that of Fe/Al-P which decreased with the distance from the coast.The spatial distribution of OP had no obvious rule in direction from the coast to the open sea which was opposite to that of IP. Bio-available phosphorus(BAP) accounted for 42.22%-56.99% of TP that was higher and would be released under suitable conditions, then used by aquatic organisms. Based on the results,phosphorus had a certain release risk in northern Hangzhou Bay, so it was necessary to formulate corresponding measures to prevent in the ecological environment management.