Abstract: Objective To investigate behavioral differences in models with depression between C57BL/6J and NIH Swiss mice with different genetic backgrounds,to provide references for selection of examination animals in anti- depression drug researches,and to provide the useful animal models for invcstigating the effects of genetic factors on occurrence of depression.Methods Behavioral manifestations of depression in C57BI/6J and NIH Swiss mice (n=14 each) were detected under stress conditions using forced swimming test and tail suspension test.Open field test was used to detect the spontaneous motility of two kinds of mice.Results The immobility time of C57BL/6J mice was significantly longer than that of NIH Swiss mice [ (133.198 ± 5.749) s vs (80.265± 10.939) s,P=0.000] in forced swimming test,which was contrast to that in tail suspension test [ (151.315±12.161)s vs (95.107±14.649)s,P=0.007].Howevcr in open field test,no diffcrcncc was found in total distance,standing number,movement time,total distance in fringe area,movement time in fringe area,total distance in central area and movement time in central area between the two kinds of mice.Conclusion C57BL/6J mice are easier to show the depressive-like behavior under stress conditions,while NIH Swiss mice show a certain of depression resistance.These different behavioral manifestations in two different kinds of mice may be caused by genetic factors.