The Kumamoto oyster (Amemiya, 1928) is mainly distributed in Eastern Asia, from the southern coast of China to Korea and the Ariake Sea of Japan. Compared to other oysters, is known for its flavored meat and firm texture, and it is therefore preferred in commercial markets over other commercial oyster species. It has been one of the most important commercial species in the shellfish industry on the west coast of America since the 1950s. In China, the wild population of is abundant and is considered an important wild fishery resource. In our laboratory, two strains of have been developed for artificial hatchery breeding in recent years. Hybridization breeding is one of the important methods for developing a new strain of . Moreover, triploid marine bivalves generally have growth and survival advantages over common diploids. Therefore, hybridization for marine bivalves has gained increasing interest for scientists. In the present study, the hybrid diploids and triploids from two strains of the Chinese population and American population of were induced to evaluate the hybridization effect and triploid advantage. The conditions for larvae and adult rearing were the same throughout the entire period. The larvae were reared in indoor tanks, with a density of 4-5 individuals per milliliter water. The juveniles were farmed on the sea, with 40-45 individuals per sting of attachment. The results showed that the hybrid diploids had heterosis for cleavage rate (13.61%) and D larvae rate (5.67%) compared to that of the controls, while the larvae of hybrid diploids had negative heterosis for their shell height growth (-0.43%). However, the juveniles and adults had heterosis of 3.96% and 6.65% for their shell height and shell length, respectively. On the other hand, the hybrid triploids had a growth advantage during the entire period, with high levels of advantage in the late growth stage. The larvae had a growth advantage of 3.69% on average, and the juveniles and adults had an advantage of 12.69% and 13.64% for their shell height and shell length, respectively. The hybrid triploids had negative survival rate from 3 days to 180 days, with a highest value of -48.72% at 15 days. However, a positive survival rate of 6.70% was detected at 360 days. In contrast, the hybrid diploids had a higher survival rate compared to that of the hybrid triploids, with mean survival advantages of 10.44% and 4.59% for the larvae and adults, respectively. The hybrid triploids had a significant growth advantage in the entire period and had a positive advantage of survival rate in the adults, suggesting that the advantages of hybrid triploids resulted from triploidy advantage and partial heterosis.