Objective:To investigate the influence of gender difference on the activation of platelets in septic rats.Methods: Totally 20 female and 20 male SD rats were randomly divided into four groups: male sham-operated group, female sham-operated group, female septic group, and male septic group, with each group containing 10 rats．Sepsis model in the last two groups was produced by cecal ligation and puncture (CLP); rats in the sham-operated group received no CLP．The rats were sacrificed 24 hours after surgery; the blood samples were collected for blood routine test; and the serum β-TG levels were detected by ELISA assay. Serum estrogen (E2) levels were detected by radioimmunoassay.Results: The blood platelet counts were decreased in both septic rats of both genders; the count in female rats was significantly higher than in the male rats (P<0.01). The serum β-TG levels were increased in septic rats of both genders; the level in the female rats was significantly lower than that in the male rats (P<0.01). The blood platelets count in female or male septic rats was significantly positive correlation with the level of serum estrogen and the β-TG expression in female or male septic rats was significantly negative correlation with the level of serum estrogen(P<0.05).Conclusion: There is a gender difference in the activation of platelets in septic rats, and the endogenous estrogen may have protective effect on the platelets of female septic rats.