The swimming crab Portunus trituberculatus (Crustacea: Decapoda: Brachyura), is an important commercial crab, widely distributed in the coastal zones of Japan, Korea, China and Southeast Asia countries. In this paper, the activity difference of five immune factors among different parentages of P. trituberculatus following the time extension were compared at different desiccation temperature, 10 ℃, 20 ℃ and 30 ℃. The five immune factors were acid phosphatase (ACP), alkaline phosphatase (AKP), catalase (CAT), nitrogen monoxide (NO), peroxidase (POD), respectively. The results showed that no significant difference was found among the parentages for the enzyme activity of ACP, but there existed some differences, more or less, for the other immune factors. The profile of the content of NO following the time extension has the same trend with the ability of the desiccation tolerance in three parentages, and this suggests that the content of NO can be used as a marker of desiccation tolerance for the inbreeding of P. trituberculatus.