By the methods of experimental ecology,a 5-3 factorial experiment was conducted to determine the effects of salinity and dietary protein levels on molt and growth of Litopenaeus vannamei.The experiment lasted 30 days. L.vannamei at an initial average weight of (2.01?0.02) g were divided into triplicate groups and were observed at salinities of 6,12,18,24,30 and protein levels of 30%,36%,42%.The results showed that the relative weight gain of molting decreased with increasing salinity,being the highest at salinity of 6.The relative weight gain of molting was affected significantly by different salinities and dietary protein levels,and the interactions of them(P＜0.05).The specific growth rate increased with increasing salinity,it was affected significantly by the different salinity and dietary protein levels(P＜0.05),but it was not affected significantly by the interactions of them.The molting frequency increased with increasing salinity low salinity levels(P＜0.05),being the highest at salinity of 18,then it decreased with further increasing salinity.At the different dietary protein levels,the higher molting frequency was obtained in experimental group with feed to the medium dietary protein levels diet(36%).The molting frequency was affected significantly by the different salinity and dietary protein levels(P＜0.05),it was not affected significantly by the interactions of them.The intermolt period was first prolonged,then shortened with the increase of salinity.The intermolt period was affected significantly by the difference salinties(P<0.05),but not affected significantly by the dietary protein levels and the interaction of them.