Objective To evaluate the feasibility, safety, and efficacy of a new surgical method of U-shaped myometrial excavation and modified suture approach with uterus preservation for diffuse adenomyosis. Methods From January 2012 to December 2014, 198 patients with diffuse adenomyosis were surgically treated using this novel procedure in Zhengzhou Hua-Shan Hospital. Degree of dysmenorrhea, menstrual blood volume, serum CA 125, and uterine size before and at 1 month, 3 months, 6 months, 12 months, and 24 months after surgery were compared. Results Postoperatively, VAS score of dysmenorrhea, menstrual blood volume, serum CA 125 level, and uterine size significantly decreased at 1 month, 3 months, 6 months, 12 months, and 24 months from presurgical levels (all p < .001), but there were no differences at the follow-up time points. Two patients recurred at 18 months and 23 months after surgery, but both recovered after repeat surgery. Interestingly, 2 other patients recrudesced at 10 months and 12 months after surgery. In addition, only one patient was found to have a postoperative anaemia with fever, conservatively managed without surgery. Conclusion U-shaped myometrial excavation and modified suture approach with uterus preservation is a safe and feasible surgical approach to treat diffuse adenomyosis, with favourable outcomes.