Random amplified polymorphic DNA (RAPD) technique was employed to detect the DNA polymorphism in 30 individuals of natural population of Pleuronectes yokohamae. 20 arbitrary primers selected from 48 primer were used and 148 clear , repeatable RAPD bands were generated in which 94 bands were polymorphic. All the primers are polymorphic primer. Each primer used for the detection could produce 4～13 molecular markers with the average of 7.4. DNA fingerprints varying in length from 200～2 000 bp. The percentage of polymorphic fragments was 63.51 % , while the index of Shannon diversity was 0.2824 and the index of gene diversity was 0.1991. Every individual had genetic difference and the genetic distance between individuals was from 0.0148 to 0.1963. Comparing the genetic diversity of Pleuronectes yokohamae s with that of other fishes , the experiment revealed that the genetic diversity of Pleuronectes yokohamae was at middle level. This result will give date for the future study of genetic diversity in Pleuronectes yokohamae.