Female southern flounder(Paralichthys lethostigma)grow larger than males.Therefore,allfemale production will maximize profit potential for the culture of this species.It may be effective to develop protocols to produce allfemale southern flounder through induction of meiotic gynogenesis with the cryopreserved heterologous sperm of Lateolabrax japonicas.To test methods for inducing diploid gynogenesis in southern flounder using heterogenous sperm,the UV was used to inactivate sperm and pressure shock was used to prevent extrusion of the second polar body.The results of experiments showed that gynogenetic diploid can be induced by inactivated heterogenous sperm because that hybrid would die before hatching.Diploid gynogenesis was induced by activating egg development with UV irradiated sperm(80 mJ/cm²) 4-5 min after fertilization(18 ℃),and then 65 MPa pressure treatment for 6 min.Flow cytometry and microsatellite DNA analysis were used to demonstrate that the gynogenetic fry are diploidy.These results indicate that the use of UV irradiated sperm from Lateolabrax japonicas for activation of flounder eggs and pressure shock for polar body retention is an effective method to produce gynogenetic diploid in southern flounder.