In order to obtain large and high quality pearls, the methods of the pearl culture in visceral mass combined with inserting large pearlnucleus cocultured by dissociating mantle cell were studied. The mantle cell was cultured by two different culture mediums that were named medium 1 and medium 2. The cell viability was detected at the different time points (2, 4, 6 and 12 h) during the process of culture. Then large pearlnucleus was cocultured by the two different dissociating cell groups. 500 Hyriopsis cumingii, divided into two groups, were separately inserted with the two kinds of cocultured pearlnucleus in their visceral mass. The results showed that the cell viability significantly increased with the cultured time in both culture mediums . The cell viabilities at 6 h and 12 h were both obviously higher than those at 4 h and 2 h (P<0.05), the difference of the cell viability was insignificant between the groups of 6 h and 12 h (P>0.05). As for the two different culture mediums, the difference of the cell viability at 2 h was insignificant (P >0.05). While, at 4 h，6 h and 12 h, the cell viability of medium 2 was apparently higher than that of medium 1 (P<0.05). The pearlnucleus cocultured by the medium 2 was attached with more cells than that by medium 1. After 5month cultivation , large and glossy pearl with 0.8 mm nacrum was obtained in the group of medium 2. Howere, the rate of pearlnucleus without nacrum in the group of medium 1 was much higher than that in the group of medium 2. The research indicated that the improved culture medium was more beneficial to the mantle cell culture and the nucleated pearl culture in visceral mass of Hyriopsis cumingii, which provides practical basis for the mantle cell culture and theoretical foundation for the large nucleated pearl culture in freshwater mussels.