Abstract: A method for identifying the genetic sex of Portunus trituberculatus is provided. The SNP markers provided by the present invention presents biallelic heterozygosity in male individuals, but presents homozygous allele type in female individuals, and can be detected by PCR amplification and sequencing method, HRM method or KASP method. The detection method is flexible and the results are stable. Among them, the KASP and HRM detection methods have high throughput, fast detection speed, and simple application. It provides an important tool for the breeding of all-female population of P. trituberculatus.