Abstract: Objective To study the effect of +Gz stress on testosterone(T) and cortisol(C) levels and T/C in saliva of pilots. Methods Forty-seven pilots of high performance fighter were included in this study. Saliva samples were taken before and after they were exposed to +6.5 Gz, +7.0 Gz and +8.0 Gz. T and C levels in saliva were measured by chemiluminescent immunoassay. Results Nosignificant difference was found in the T level in saliva of the pilots before and after exposure to +6.5 Gz, +7.0 Gz and +8.0 Gz. The C level was significantly higher in saliva of the pilots after exposure to +6.5 Gz, +7.0 Gz and +8.0 Gz than before exposure to them(P<0.05) and after exposure to +8.0 Gz than before exposure to +6.5 Gz, +7.0 Gz and +8.0 Gz(P<0.05). No significant difference was found in the T/C in saliva of the pilots after exposure to different +Gz stresses although it tended to change. ANOVA analysis showed that the type of fighter, the age and total flight time of pilots had no effect on the T and C levels and T/C after exposure to different +Gz stresses. The T level was not related with the C level in saliva of pilots after exposure to different +Gz stresses. Age was positively related with baseline T/C. Conclusion The elevated C level in saliva of pilots after exposure to +Gz indicates that saliva can be used as an indicator of stress and fatigue in pilots.