Influences of salinity on hatching rate and larval vitality in NEW GIFT Nile Tilapia(Oreochromis niloticus) were investigated.Eight different levels of salinity were set as follows: 3‰,6‰,9‰,12‰,15‰,18‰,21‰,24‰ and freshwater at temperature of 28±0.5℃.The hatching time,incubation period,hatching rate and deformity rate of the embryos were observed.Four broods of newly hatched larvae were used to for starvation tests and SAI (survival activity index) evaluation.The normal embryonic development and high hatching rate (89.0%-92.7%) were observed at salinities from 6‰ to 15‰,while low hatching rate occurred at a salinity of both less than 3‰ and more than 18‰.The result show that the suitable salinity for the survival of larval hybrid tilapias ranges from 3‰ to 15‰.Salinity below 2‰ or over 17‰ is not suitable for the larvae.At salinities from 6‰ to 15‰,the SAI values were high.The SAI of larvae was positively related with hatching rate of fertilized eggs.