·AIM:To compare the curative effect of the external dacryocystorhinostomy(DCR),using two different patterns of flap anastomosis with suturing of two flaps or anterior flap.·METHODS:Fifty-six eyes 48 patients were randomized and assigned to two groups on the basis of the pattern of flap anastomosis.In double-flap group with 25 eyes 20 patients,posterior and anterior flaps were separately sutured.In single-flap group with 31 eyes 28 patients,only the anterior flaps were sutured after resecting of both posterior flaps.·RESULTS:The time of follow-up was 6-10 months for all patients.The final success rates in double-flap groups were 92% and in single-flap group were 90% respectively.There was no significant statistical difference in success rate between the groups.·CONCLUSION:DCR with double-flap anastomosis has no advantage over only anterior flap.Anastomosis by only anterior flap and resected posterior flap is easier to perform and does not appear adversely to affect the outcome of DCR surgery.·