Portunus trituberculatus is an economically important marine crab distributed along the coast waters of China, Japan, Korea and Malaysia Islands.In recent decades, the wild population has been constantly decreased due to overfishing and habitats destruction.To protect and recover the P.trituberculatus resources, a large scale of stock enhancement has been carried out in the coastal waters of China.As the stock enhancement activities may change the genetic variability and genetic composition of the recipient wild populations, it is necessary to carry out genetic monitoring of broodstocks and their offspring for the long-term sustainability of wild populations.In present study, genetic diversity and population structure of 4 P.trituberculatus broodstock populations used in stock enhancement were detected according to the sequence of mitochondrial control region.155 mtDNA haplotypes were observed in 301 P.trituberculatus individuals, among which only 20 haplotypes were shared by different populations.The gene diversity index ranged from 0.972 3 to 0.993 0, while the nucleotide diversity index ranged from 0.021 2 to 0.023 6, both of them showed a high level of genetic diversity for broodstock populations.The result of AMOVA suggested that 98.70% of the genetic differentiation occurred within populations.The F_st values between populations ranged from -0.002 5 to 0.023 0, which indicated a little genetic differentiation and no significant genealogical structure among 4 populations together with the result of AMOVA.And no pedigree branch corresponding to different populations was observed in the neighbor-joining tree.The results above suggested that wild populations from where the broodstocks were collected had little genetic differentiation between each other.To sum up, each of the 4 broodstock populations had abundant genetic diversity and similar genetic structure with the wild populations to be supplemented, which reflected good quality of the germplasm resource.The mismatch distribution of pairwise nucleotide and the negatively selective neutrality test suggested that P.trituberculatus of the south Bohai Sea and north Yellow Sea had experienced demographic or spatial expansion in history.