Objective: To investigate the clinical efficacy, long-term control, and safety of an integrated treatment approach for adenomyosis without fertility requirements, incorporating MRI-based classification, GnRH-a pretreatment, high-intensity focused ultrasound (HIFU) ablation (Haifu Knife), sequential maintenance with Mirena/Dienogest, combined with close follow-up every 3 months and multiple supplemental treatments every 6–12 months. Methods: A retrospective analysis was conducted on 136 patients with adenomyosis without fertility requirements admitted to the gynecology department of our hospital from January 2019 to December 2025. Patients were stratified based on MRI classification, clinical symptoms, and the presence of adenomyoma: Those with simple adenomyosis and menorrhagia received GnRH-a + HIFU + Mirena; those with adenomyoma and severe dysmenorrhea received GnRH-a + HIFU + Dienogest. All patients underwent routine follow-up every 3 months post-treatment, with HIFU supplemental ablation performed every 6-12 months for residual or recurrent lesions, accompanied by long-term drug management. Dysmenorrhea VAS scores, menstrual volume, uterine volume, clinical efficacy, recurrence rate, and complications were observed before and after treatment. Results: All 136 patients completed treatment and standardized follow-up, achieving an overall clinical efficacy rate of 88.2%, with dysmenorrhea relief in 89.7%, menstrual volume improvement in 87.5%, and a mean uterine volume reduction of 32.6%. The median follow-up period was 24 months, with an overall recurrence rate of 11.8%. Recurrent cases were effectively controlled through multiple HIFU supplemental treatments without severe complications. Conclusion: For patients with adenomyosis without fertility requirements, the integrated management approach combining MRI-guided GnRH-a + HIFU + Mirena/Dienogest sequential therapy, frequent close follow-up, multiple supplemental ablations, and long-term drug maintenance significantly improves clinical symptoms, reduces uterine volume, and lowers recurrence risk. This approach is stable, safe, non-invasive, and aligns with the principles of standardized and individualized conservative treatment for adenomyosis, offering a new standardized uterine-preserving treatment paradigm for patients without fertility requirements.