Complete diallel interspecific hybridization between Argopecten purpuratus Lamarck and A.irradians irradians Lamarck was conducted under laboratory conditions.Bidirectional fertilizations and successful hatching were observed for all crosses.Fertilization rate, hatching success, larval survival, and growth for whole life stages (larvae, spat and adult) were compared among hybrids and pure populations.No significant difference in the fertilization rate and hatching success were found among experimental groups (P > 0.05).Notable heterosis (i.e., greater than 1% of the mid-parent values) was detected for growth throughout the whole life span and for survival during the larval stage.The influence of maternal effect and mating type (intra-vs.interspecific crosses) on growth for all life stages examined (except day 30 and day 90) was significant (P < 0.05), but only mating type had a significant effect (P < 0.05) on larval stage survival.Genetic analysis using internal transcribed spacer 1 revealed that the survivor spats from cross groups contained DNA from both parent species, which confirmed the hybridization between the two species.H.E.staining paraffin slice for the gonad of mature hybrids was performed.Male gonad was found obsolescence without any active sperm while female gonad was developed with abundant normal appearance eggs.But the hybrids eggs could not back-cross with the parental species what expressed typical postzygotic isolation—hybrid sterile.The study described an attempt to improving the scallop breeding by interspecific hybridization.