Objective To examine the effects of maternal rats exposed to chronic unpredictable stress before pregnancy on the behaviors and brain monamine of their adult male offspring.Methods Sixteen SD rats were divided into chronic unpredictable stress (CUS) group and controls.CUS rats were exposed to 21 days chronic unpredictable stressors ,and the controls were stress-free.Ten days after the last stressor, all the female rats were caged with sexually experienced males of the same strain.Then we performed the following experiments on the two months male progeny, sucrose consumption measuring anhedonia, Morris water maze measuring cognitive function and high performance liquid chromatography detecting the contents of monoamine.Results The sucrose consumption showed that both sucrose intake and sucrose consumption percentage of the control progeny were higher than those of the CUS progeny ( sucrose consumption: ( 10.23 ± 4.12 ) g vs ( 6.48 ± 3.19 ) g; sucrose consumption percentage: ( 85.43 ± 20.15 ) % vs (60.98 ± 24.65 ) % ) (P ＜ 0.05 ).The number of times crossing the removed hidden platform in the CUS progeny ( 1.64 ± 1.69) was significantly fewer than that in the control progeny (4.17±2.29 ) in Morris water maze (P ＜ 0.05 ).The contents of serotonin in the hypothalamus of CUS progeny ( ( 500.17 ± 80.94 ) ng/g tissue) was lower than that of the control progeny ( ( 569.63 ± 50.91 ) ng/g tissue) (P ＜0.05) ,while the norepinephrine in the hippocampus of CUS progeny( (2315.01 ± 1397.12) ng/g tissue) was higher than that of the control progeny( (907.56 ± 207.27) ng/g tissue) (P＜0.05) by high performance liquid chromatography.Conclusions Depression or stressful events before pregnancy of dams result in anhedonia, decreased spatial memory and abnormalities in brain monoamine of their adult male progeny.