Objective To explore the mediating effects of rumination and its subtypes on the relationship between negative life events and depressive symptoms in treatment-naive depressed patients.Methods Sixty-two treatment-naive depressed patients completed the center for epidemiologic studies depression scale (CESD),rumination response scale (RRS),and life event scale (LES).Results ① The scores of CESD were positively correlated with total score of RRS,brooding score of RRS,and negative LES score (NLES) in depressed patients (r=0.66,P＜ 0.01;r =0.50,P＜ 0.01;r =0.51,P＜ 0.01).The total score of RRS and brooding score of RRS were positively correlated with NLES(r=0.45,P＜0.01;r=0.47,P＜0.01).② The total score of RRS played a mediating role between NLES and CESD (indirect effect=0.12,95％ CI =0.04 ～ 0.23).③The brooding of RRS played a mediating role between NLES and CESD (indirect effect =0.07,95％ CI=0.02～0.15).Conclusion The RRS and the brooding of RRS exert mediation effects on the relationship between NLES and CESD in patients with depression.