Abstract:[Abstract] Objective To investigate the effects of chronic restraint stress on the depressive-like behavior of male and female SD rats with different restraint duration. Methods Sprague-Dawley rats (male and female) were subjected to restraint stress 10h/14 h daily for 28 days.After that, sucrose preference test, open-field test, novel object test, were performed for all the rats to observe the effects of different restraint duration of chronic restraint stress on the depressive-like behaviors in male and female SD rats. Results For the 14h/28dCRS group, including male and female rats, the movement time and central activity time were reduced, sugar consumption index were decreased, novelty exploration time and frequency were reduced, latency were increased, numbers of nose pokes were reduced, and these results were significantly different compared with the control group. There were individual indicators that showed significantly difference for all the above-mentioned behavioral tests of the 10h/28dCRS group. 14h/28d CRS male group in syrup consumption index decreased significantly, the corresponding female rats did not significantly reduce. 10h/28dCRS male group in the central motion time less than that of the control group, and latency was prolonged and exploration time was shortened, while the corresponding female rats had no significant difference. Conclusion 14h/28dCRS rats in the sucrose preference test, open-field test,novel object test were exhibited depressive-like behavior, but 10h/28dCRS male rats showed a trend of depressive-like behavior. Chronic restraint stress was more likely to lead to depressive-like behavior in male rats.