The invention provides a male specific DNA marker of oplegnathus punctatus, wherein the sequence of the DNA fragment on a Y chromosome is shown in SEQ ID NO: 1; the sequence of the DNA fragment on a Xchromosome is shown in SEQ ID NO: 2. The DNA fragment on the Y chromosome is 12 bp more than the fragment on the X chromosome, and the fragment is the DNA fragment peculiar to the Y chromosome. According to the invention, two homologous and different DNA fragments on the X and Y chromosomes are screened from the whole genome sequence of the oplegnathus punctatus, and a method for identifying theheredity sex of the oplegnathus punctatus is further established; and the method can be used for quickly, accurately and effectively distinguishing the heredity sex of the oplegnathus punctatus. According to the method, a specific target band amplified in a male individual cannot be amplified by a female individual, and the product can be resolved by agarose electrophoresis, so that the time for accurately identifying the heredity sex of the oplegnathus punctatus is shortened, and the method is suitable for identifying the heredity sex of the oplegnathus punctatus in a simple environment of aculture farm, and the detection time and the cost are saved. The method has important significance and application value in sex identification, seedling breeding and family selection and breeding of the oplegnathus punctatus.