Objective:To assess the transverse abdominal incision sutured by onelayer outside peritoneum in open appendectomy. Methods:In a randomcontrolled study,724 patients underwent open appendectomy for appendicitis from August 2004 to December 2006 were analyzed.The patients were operated randomly with the transverse incisions sutured by onelayer outside peritoneum in the downright abdominal part(group A)or with the routine McBurney's incision (or transverse abdominal incision ) sutured by multilayer(group B). Results:In the patients with suppurative or gangrenous appendicitis,those in group A had significantly shorter operating time,shorter length of hospital stay and lower rates of incision infection than those in group B (P＜0.01);however,the differential postoperative pain in the two groups was not found (P＞0.05).In the patients with simple acute appendicitis,those in group A got no more advantages than that in group B (P＞0.05),but also accompanied with more severe postoperative pain (P＜0.01). Conclusion:In the patients underwent open appendectomy for suppurative or gangrenous appendicitis,the transverse incision sutured by onelayer outside peritoneum in the downright abdominal part is safe and simple,and can provide more advantages than the routine incision sutured by multilayer,which should be taken as a standard incision.However,in the patients with simple acute appendicitis,the routine McBurney’s incision (or transverse abdominal incision) sutured by multilayer should be selected firstly.