To investigate the tetraploid induction effect between two allotetraploid oysters (GGAG—GGA ♀×GG ♂ and AAGG—AAG ♀×GG ♂) under varying cytochalasin B (CB) concentration (0.2, 0.4, 0.6, 0.8 mg/L), salinity gradient (6, 8, 10, 12) and induction duration (10, 15, 20, 25 min), we analyzed the cleavage rate, hatching rate, tetraploidy rate and induction efficiency. At the same time, the growth and survival of the early larvae were analyzed. The results showed that the optimal method of inducing tetraploid of GGAG was 0.6 mg/L of CB and 15 min. The tetraploidy rate of (42.75± 2.89)% was obtained with the method. The salinity 8 and 15 min was also the optimal method, with which the tetraploidy rate of (32.28±1.97)% was obtained. For AAGG, 0.6 mg/L of CB and 20 min was optimal, with which the tetraploidy rate of (47.03±2.66)% was obtained. The salinity 10 and 15 min was the optimal method, with which the tetraploidy rate of (33.06±1.18)% was obtained.