Abstract: The contents of total phosphate and free- phosphate in aquatic products were studied by bismuth phosphomolybdate blue spectrophotometric method.The results showed that the contents of total phosphate and free-phosphate in six kinds of frozen aquatic products were different.These samples were frozen peeled shrimp, frozen flower clams, frozen octopus, frozen scallops, jellyfish and frozen squid.The contents of total phosphate were between 0.4318 g /kg and 6.7995 g /kg in six kinds of samples.The contents of free- phosphate were between0.1164 g /kg and 4.6107 g /kg.After the samples were soaked, the phosphate contents decreased significantly during soaking.The contents of total phosphate and free- phosphate in frozen peeled shrimp, frozen ribbonfish, frozen scallops and frozen squid decreased faster in boiling water than in cool water.The shrimp was soaped for 1.5hours in sodium tripolyphosphate, sodium pyrophosphate, sodium hexametaphosphate and cmpound phosphate solution.The results showed that to make phosphate residues on the shrimp not exceed 10 mg /kg, and has good water—holding capacity, the concentration of four kinds of soak liquid should be more than 2%, less than 3%.Bismuth phosphomolybdate blue spectrophotometric method has better sensitivity and recovery than vanadiummolybdenum-yellow-spectrophotometry.