Abstract： Objective To investigate long-term effect on radiofrequency heat-coagulation (RF)endometrial ablation in treatment of anovulatory dysfunctional uterine bleeding (DUB). Methods From Jul.2001 to Nov. 2009, 1 196 patients with DUB who were failed by medical treatment( including 127 patients with dysmenorrheal) were enrolled into this study in Jinan Millitary General HospitaL Those patients were divided into two groups according to age:427 patients at age of or more than 45 years (average age 48 years) in Group A who were treated by RF procedure for amenorrhea;769 patients at age of less than 45 years old (average 37 years) in group B were treated by RF for controlling excessive menstrual bleeding. All the patients had the results of menstrual score (pictorial blood loss assessment chart, PBAC), hemoglobin (Hb) ,endometrial curettage pathology and hysteroscopy examination immediately after RF procedure; Some patients still had another endometrial curettage pathology and clinical results in 6 months after RF. The mean follow-up time was 72 months ( range:6 to 100 months). The evaluation criterion for RF treatment was to use optimal and significant effect measurements. For group A, the optimal treatment effect (cure) was defined as bleeding cessation and achieving amenorrhea that continued for more than 12 months after treatment. For group B, the optimal treatment effect (cure) was also defined as bleeding cessation and resuming normal menstruation which continued for more than 12 months after treatment. Significant treatment effect was defined as irregular, minor bleeding, but PBAC score less than 100 within 12 months. If patient symptoms and PBAC scores did not change compared with those before treatment, the treatment was defined as failure. For dysmenorrhea, the optimal treatment effect was disappearance for more than 12 months, the significant treatment effect was remission, and treatment failure was not changed from the pre-treatment baseline. The effective rate was the sum of that of the optimal and significant effect. One hundred and twentyfive patients with DUB treated by agents at the same time were chosen as control group. Results ( 1 ) The recent and long-term effective rates for bleeding cessation by RF: the total recent effective rates within 1 months were 94. 82％ ( 1134/1196), including 96. 5％ (412/427) in group A and 93.9％ (722/769) in group B. The total curative rates for dysmenorrheal were 82. 7％ ( 105/127 ), including 86. 4％ ( 38/44 ) in group A and 80. 7％ ( 67/83 ) in group B. Pathology examination after hysteroscopy immediately after RF showed a completely and whole destroyed endometrium in group A, and a little rested endometrium in group B. The long-term effect rates for bleeding cessation by RF after 12, 24 and 36 months were 92. 55％ (969/1047), 93.9％ (866/922) and 93.7％ (609/650), respectively. PBAC and Hb in group A and group B within 12, 24, 36 and more than 36 months were improved significantly ( P ＜ 0. 05 ). (2) Complications : the major complication was irregular minor bleeding in 1 to 2 months after treatment, the rate was 8.03％ (96/ 1196). The second one was menorrhea in 3 months after RF, the rate was 5. 18％ (62/1 196 ). This condition was corrected by the second RF. No hysterectomy was performed on those patients. Conclusion RF is the safe, efficient and minimal invasive procedure in treatment for DUB. The mechanism of keeping longterm curative effect and preventing recurrence is due to endonetrium inactivation and fibrosis by thermocoagulation.