Objective Using behavioral testing to study the influence of simulated astronautic environment on cognitive function in rats.Methods Tail suspension, separation, isolation and circadian rhythms change are used to simulate the stronautic environment. Reward conditioning test and Morris water maze (MWM) test are used to measure cognitive function after 14days and 28days of simulated compound astronautic environment. Results Upon reward conditioning test, compared with control (Con) group , the compound environment (CE) group showed the lower nose pokes(P＜0.05) in 14 days. In 28d, CE group was significantly less than Con group and Tail restraint(TR) group in nose pokes(P＜0.01). Upon the Morris water maze(MWM) test , compared with Con group and TR group, CE group exhibited longer escaping latency and total distance in 14d (P＜0.01，P<0.05). At 28d, the difference became larger (P＜0.01). Con group and TR group were no difference in reward conditioning test and MWM test. Conclusions Simulated compound astronautic environment can induce serious cognitive function deficit, and the cognitive function deficit was more stable in 28d.