AIM: To describe a simple modification of fashioning the mucosal flap for endonasal endoscopic dacryocystorhinostomy (EES-DCR) in Asians and investigate its efficacy. METHODS: A total of 120 patients with unilateral primary chronic dacryocystitis (PCD) were randomized into two groups: the new shaped nasal mucosal flap group (group A) and the removed nasal mucosal flap group (group B). All patients underwent standard EES-DCR. Patients in group A were performed a new shaped nasal mucosal flap covering the bared bone around the opened sac and those in group B was removed the nasal mucosal flap uncovering the bared bone. Patients were followed up for one year. The occurrence of granulation tissue, the proliferation of scar tissue and success rate of EES-DCR was compared. RESULTS: In the present study, complete postoperative data were acquired from 54 patients in group A and from 57 patients in group B. During process of review, the occurrence of granulation tissue was at the ostium margins account for 15% (8/54) in group A and 39% (22/57) in group B (P<0.05). At the one-year review, scar tissue was present in 5 patients in group A compared with 18 in group B (P<0.05). The success rate of EES-DCR was 98% (53/54) in group A and 84% (48/57) in group B (P<0.05). CONCLUSION: The simple modification of fashioning nasal mucosal flap can effectively cover the bared bone around the opened sac and reduce formation of granulation tissue, lessen the risk of scar tissue formation and closure of ostium, thus improve the success rate of EES-DCR in Asians.