Abstract: Objective To investigate the method and timing of reconstruction of anal stenosis induced by scar contracture after repair of defect in perineal region with paraumbilical flap using random pattern flap. Methods Ten patients who suffered anal stenosis induced by scar contracture after the first phase repair of defect of perineal region with paraumbilical flap were hospitalized from July 2009 to September 2015. Eight patients were with central type scar contracture of perineal region after healing of burn wound, and two patients were with lesion of perineal region which had been excised. In 6 to 8 weeks after the first phase surgery, two or three random pattern flaps were designed around the narrow anus in the survived paraumbilical flap. After thorough release of the narrow anus, the random pattern flaps were transferred to enlarge the anus. The tip of the lifted triangular flap was transferred to insert into the anal canal. The skin of anal canal or rectal mucosa was pulled out to be crossly-stitched with the flap. Results All the patients′ narrow anuses were released and enlarged with one operation, and the diameters of the narrow anuses were enlarged to 2.0 to 3.0 cm. During follow-up of 6 to 36 months, the anal stenosis was totally released, and the symptom of difficult defecation was significantly improved; 7 patients were excellent and 3 patients were good with evaluation of clinical criteria of anus function; no symptom of anal stenosis or rectal mucosal prolapse was observed any more. Conclusions In 6 to 8 weeks post repair of defect in perineal region with paraumbilical flap, designing of random pattern flap in the survived paraumbilical flap to enlarge and reconstruct the narrow anus has good therapeutic effects on anatomical narrow and difficult defecation.