Objective To explore the correlation of preoperative psychological status and postoperative functional outcome of patients undergoing total knee arthroplasty(TKA).Methods From July to October 2010,111 patients with osteoarthritis(155 knees)who accord with our standard underwent TKA in our department.After the patients were admitted,their mental condition was evaluated by the Hospital Anxiety and Depression Scale(HADS).If HADS was over 8 points,the patient was believed to have anxiety and depression,and assigned into mental group.There were 21 and 90 patients in the mental and control group.The postoperative knee functional outcomes were compared between the two groups at 1,3,6 months according to the WOMAC score and HSS score.The correlation of preoperative HADS psychological scores and WOMAC scores,HSS scores after 1,3,6 months were analyzed by the Pearson correlation analysis.Results The 1,3,6 month postoperative WOMAC scores of mental group were higher than the control group(t=0.226,0.242,0.250,P＜0.05).The 1,3,6 month postoperative HSS scores of mental group were lower than the control group(t=0.233,0.254,0.227,P＜0.05).However,the preoperative anxiety and depression of HADS and WOMAC scores,and HSS score of 1 month,3 months after operation for the Pearson correlation analysis showed P＞0.05.The preoperative anxiety and depression had a positive correlation with knee pain of 6 months postoperation(r=0.613,0.530,0.500,0.473,P＜0.05),a negative correlation with the function(r=-0.551,-0.642,-0.486,-0.524,P＜0.05),the correlation with activities,muscle strength,flexion deformity,stability,stiffness showed r values were between-0.31 and 0.31,indicating no significant correlation among them(P＞0.05).Conclusion Preoperative anxiety and depression have a negative impact on postoperative knee functional outcome.