Reciprocal hybrids of olive flounder ♀(Paralichthys olivaceus)×summer flounder ♂(P. dentatus), olive flounder ♀(P. olivaceus) × barfin flounder ♂(Verasper moseri), olive flounder ♀(P. olivaceus) × turbot ♂(Scophthalmus maximus) were performed by artificial fertilization from 2005 to 2008. And data of hybridization on eight flatfish species in previous reports were also collected including barfin flounder (V. moseri) × spotted halibut (V. variegatus), stone flounder (Kareius bicoloratus)× starry flounder (Platichthys stellatus), summer flounder (P. dentatus) × southern flounder (P. lethostigma) and olive flounder (P. olivaceus) × spotted halibut (V. variegatus). The hybrid compatibilities of interspecific crosses on these eight flatfish species were analyzed. According to Russell’s definition, hybrid fitness was scored 1 when the offspring of reciprocal crosses were both viable. The hybrid fitness was scored 0.5 whe one direction of reciprocal crosses was viable, and hybrid fitness was scored 0 when the offspring of reciprocal crosses were both inviable. Meanwhile, the ribosomal RNA 16S (16S rRNA) partial sequences and the mitochondrial cytochrome c oxidase subunit Ⅰ (COⅠ) partial sequences of the eight flatfishes were obtained and analyzed. Based on combined sequence data of mtDNA 16S rDNA and COⅠ, intrespecific pairwise distances were calculated and a phyogenetic tree was constructed. The relationship between hybrid fitness of the flatfishes and pairwise genetic distances was evaluated and linear correlation existed between the two（R²=0.81， P<0.01）. The hybrid compatibilities declined with the interspecific genetic distances. Our results suggested that negetive correlation exists between hybrid compatibility and genetic divergence in flatfishes. The hybrid compatibility between different species of flatfishes could be predicted by analysis of interspecific genetic distance. And these results would be good references for further hybrid breeding study in flatfish.