Objective To observe the effects of menopause on prothrombotic profiles in ovariectomized rats .Methods Thirty two healthy female SD rats of 9 to 10 months were divided into 4 groups, the control shamed and the observation groups ovariectomized .Rats in the baseline group and the early menopause group were sacrificed one week later , and the control and late menopause group 10 weeks later.The prothrombotic profiles were detected including plasma FIB , ATⅢ activity, PAI-1 levels, D-D level, vWF levels and NO concentration, TXA2 and PGI2 levels.Results In early menopause, plasma FIB increased dramatically while ATⅢactivity remained lit-tle changed.PAI-1 demonstrated an increasing trend .vWF significantly increased but NO significantly decreased .In later menopausal stage, PAI-1 increased dramatically but FIB somewhat decreased .Plasma ATⅢactivity significantly increased and vWF still remained a high level.NO increased a little.In both early and later stage, TXA2 and PGI2 simultaneously increased while D -D showed little change between groups .Conclusion Menopause plays different roles in different aspects of thromoembolism , resulting in increased risk in early menopause due to prothrombotic state and decreased risk in later menopause when new balances between profiles were established .