Objective To investigate the prevalence of anorectal pain in chronic constipation (CO patients. Methods With multi-centered stratified questionnaires investigation,the face to face questionnaires investigation was carried out on the symptoms of constipation and intensity,frequency and duration of anorectal pain in CC patients. CC and anorectal pain was diagnosed according to Rome Ⅲ criteria. Results Total 921 CC patients were investigated,and 909 questionnaires were valid. Of those,there were 258 male cases and 651 female cases,the mean age was(48. 9±18. 7)years. About 15. 1%(137/909)CC patients reported anorectal pain in last six months;of those 26 cases(2. 9%)with chronic proctalgia(CP),111 cases(12. 2%)with proctalgia fugax(PF). The percentage of pain occurred frequently or regularly in CP and PF patients was 88. 5%(23/26)and 73. 9%(82/111)respectively. The pain of PF patients was milder than that of CP patients. The detection rate of CP was higher in tertiary hospitals than in primary cares(3. 6% vs 0. 6%,P= 0. 04). There was no significant difference of PF detection rate between different hospitals(P= 0. 09). The occurrence of pain was associated with anorectal symptoms,sleeping and psychosocial condition. Conclusions CC patients are frequently with anorectal pain and more common in female,which should cause extensive concern by physicians.If necessary,the prevalence of anorectal pain in general population as well as the mechanism of the symptom need further investigation.