Abstract: The purpose of this study was to evaluate the stress indicators which can reflect the physiology of swimming crabs(Portunus trituberculatus)sensitively during air-exposure and subsequent recovery.The effects of 0.5,1.5 and 3 h air-exposure stress on antioxidant capacity and stress response of crabs with an average weight of (87.93±1.24)g were investigated by determining hepatopancreas superoxide dismutases(SOD)activity,total antioxidant capacity(T-AOC),malondialdehyde(MDA)and heat shock protein 70(HSP70)level and muscles lactate contents.Crabs were sampled at 0.5,1.5 and 3 h during exposure to air,and at 0,2,4 and 10 h during following recovery,with crabs in seawater of (22.5±0.5)℃ as control.The main results showed that:(1)No significant effects of air exposure stress on SOD activity and MDA content in hepatopancreas were observed(P>0.05).However,air exposure stress had a significant influence on the T-AOC level,the content of HSP70 in hepatopancreas and muscles lactate contents.(2)After 0.5 h air-exposure stress,the SOD activity reached the maximum value when crabs had recovered for 4 h.During the recovery from 2 h to 10 h after 0.5 h stress,the MDA contents were significantly higher than that of control(P<0.05).No significant differences of the T-AOC level in hepatopancreas were observed during recovery after 0.5 h of air exposure(P>0.05).The SOD activity was similar to control after 1.5 h and 3 h of air exposure stress,and there were no significant differences between control and time intervals(P>0.05).The MDA content of crabs exposed to air for 1.5 h increased first and then decreased during recovery,with no significant differences observed between control and time intervals(P>0.05).However,after 3 h of air exposure,the MDA content significantly increased at 10 h during recovery(P<0.05).Besides,the T-AOC level reached the maximum value at 4 h after 1.5 h of air exposure,which was significantly higher than that of control(P<0.05).For crabs exposed to air for 3 h,the T-AOC significantly increased(P<0.05)at 0.5 h during recovery and then returned to the control level in 2-10 h(P<0.05).The lactate contents of all groups reached the maximum values at 0.5 h during recovery.The HSP70 levels of different treatments reached their maximum values in 2-4 h during recovery.These results indicated that,compared to other stress indicators which were selected,T-AOC level could more sensitively reflect the physiology of Portunus trituberculatus suffering air-exposure stress.SOD activities and MDA contents could be used synergistically to indicate the physiology of crabs during recovery.