With the development of intensive aquaculture and deterioration of aquacultural environment, it is necessary to select new strains of high resistance to adverse environmental elements and diseases. Salinity is an important abiotic factor in aquaculture, affecting physiological activities in aquatic organisms. In order to select new Penaeus monodon families of low salinity resistance, salinity 0, 0.5 and 1 were used to evaluate the low-salinity-resistant ability of 11 P. monodon families. The results of acute stress experiment showed that the salinity 1 didn't have a serious impact on the survival of P. monodon. All the 11 families were able to adapt to the salinity 1, so 1 salinity stress experiment cannot be used as reference standard of assessment of low salinity tolerance. Salinity 0 and salinity 0.5 had a strong influence on the survival of P. monodon, and all the families eventually died out completely and the survival of different families at the median lethal time were significant different from each other. And results of salinity 0 stress experiment and salinity 0.5 stress experiment had a certain consistency, so salinity 0 and salinity 0.5 can be used as a reference standard to evaluate the low salinity tolerance of P. monodon. According to results of salinity stress experiments, the low-salinity-resistant ability of family J(♀61619×♂61548), family I(♀61173×♂61615), family H(♀61116×♂61625) and family K(♀61689×♂61504) was much stronger than other families, and the low-salinity-resistant ability of family G(♀61685×♂61569), family C(♀61109×♂61537), and family A(♀61119×♂61583) was the weakest. And compared with Thailand strain and Indonesian strain of P. monodon, the African strain has a stronger resistance to low salinity. This study provides four candidate families for low salinity tolerant families selection of P. monodon and has the potential to be the theoretical basis for breeding of P. monodon.