This study created a new sex identifying method of live Cyclina sinensis by observing the gonad color with an expanding kit expanding two shell openings. At the same time, a tissue observation method was improved that is suitable for sex identification of live Cyclina sinensis. The sex of live Cyclina sinensis was identified with two methods and the accuracy was checked, then cultured them and made artificial inducing spawning. To check the impact on survival and gonadal development, control group was established under the same conditions. Results showed that two methods can accurately identify the sex of live Cyclina sinensis, the success rate was 100%. The survival rates were (94.33±1.53)% and (93.33±1.53)%, respectively. And the spawning rates were (87.33±3.06)% and (84.67±1.15)%, respectively. The survival and spawning rates of control group were (95.00±2.00)% and (85.33±3.06)%. There have no significant difference with the control group in survival and spawning rates (P>0.05). It meant sex identification had no significant adverse effect on survival and gonadal development. The survival rate and spawning rate of expanding observation method were all higher than those of tissue observation method, but have no significant difference (P>0.05). The expanding observation method superior than the tissue observation method as following, (1) few operation steps, high identification efficiency, time spent only about 1/3 of the latter, conducive to sex identification of large group and hybridization between groups; (2) sex identification can be carried out in mid gonadal development, conducive to making experimental scheme; (3) no injury; (4) the integral gonadal development condition can be observed in vivo.