Abstract: Eight polymorphic loci and 25 alleles were revealed by using polyacrylamide gel electrophoresis, from 5 isozymes and 1 protein. On the account the genetic structure of population of Patinopecten yessoensis were analyzed in four sea areas in Dalian. The results showed that the distributed difference of gene frequency was bigger and there are apparent genetic distance in each hatched; population,genotype distribution was deviated Hardy-Weinberg equilibrium very much,and there are inbred relation inside population to a certain extent.