Objective:To explore the relationship between loneliness and attachment in college students and the mediating effect of rumination.Methods:Totally 545 students [239 males,306 females;average age (20 ± 3) years] were assessed with the Russell UCLA Loneliness Scale (UCLA),Experiences in Close Relationships Inventory (ECR,including attachment avoidance and attachment anxiety) and Nolen-Hoeksema Ruminative Response Scale (RRS).The structural equation model was used to research the mediating effect of rumination on relationship between loneliness and attachment.Results:The scores of UCLA,ECR and RRS were positively correlated each other (r =0.30,0.20,0.44,Ps ＜ 0.01) in college students.The inspection of the mediating effect found fit indices for hypothetical model were acceptable (x2 =16.69,df=5,NFI =0.98,IFI =0.99,TLI =0.96,CFI =0.99,AGFI =0.96,RMSEA =0.07).Path analysis revealed that attachment avoidance and attachment anxiety predicted directly loneliness (β =0.10,0.06) and rumination (β =0.05,0.16),and predicted loneliness by rumination (β =0.18).Conclusion:The rumination may be associated with loneliness and individual attachment and play a partial mediating effect between loneliness and attachment in college students.