Fish in which gynogenesis has been induced have all their chromosomes inherited from the mother and, if females are the homogametic sex, they usually are all females. Because barfin flounder Verasper moseri females grow faster than males, the production of allfemale populations is highly desirable. Due to the low volumes of semen produced by male flounder, and to eliminate any potential genetic contribution by homologous sperm, activation of flounder eggs with heterologous sperm was also necessary. To test methods for inducing diploid gynogenesis in barfin flounder using homologous sperm, the cryopreservative sperm of Lateolabrax japonicas was used to activate eggs and cool shock was used to prevent extrusion of the second polar body. Four treatments, named for their expected outcome, were employed: hybrid, haploid, triploid, and gynogenetic diploid to prove the ability of Lateolabrax japonicas sperm activating flounder eggs. Diploid gynogenesis was induced by activating egg development with UV irradiated sperm (80 MJ/cm²) for 7-9 min in seawater, and then subjecting the eggs to cold shock in -1-1.5 ℃ seawater for 60-90 min. The hybrid of could not survive to hatching, thus the offspring was allogynogenesis only and the result of microsatellite markers analysis proved this result. This work provides procedures for induction of diploid gynogenesis in barfin flounder using heterologous sperm.