Objective To evaluate the efficacy and safety of Mirabegron combined with transcutaneous tibial nerve stimulation (TTNS) in the treatment of drug-refractory overactive bladder (OAB), so as to alleviate patients'symptoms, improve their quality of life with optimized treatment plan, and provide reference for clinical practice. Methods A retrospective analysis was conducted on 56 patients with drug-refractory OAB treated at the Department of Urology of Gansu Provincial Hospital during Jan.2023 and Dec.2024. Based on the treatment methods, the patients were divided into two groups:the TTNS group and the combined treatment group, with 28 patients in either group. The daytime urination frequency, nocturia frequency, urgency episodes, urinary incontinence, functional bladder capacity (FBC), OAB symptom scores (OABSS), and incontinence quality of life questionnaire (I-QoL) scores were collected before and after treatment. The therapeutic efficacy was evaluated using the Nimodipine method. Results After 12 weeks of treatment, the 24-hour urination indicators in both groups including daytime urination frequency, nocturia frequency, urgency episodes and FBC, as well as OABSS and I-QoL scores, showed a significant improvement compared to baseline (P<0.001). The combined treatment group exhibited fewer urgency episodes than the TTNS group [ (1.07±0.66) times/24 h vs. (1.64±0.62) times/24 h, P<0.05]. However, no statistically significant differences were observed between the two groups in other urinary parameters (P>0.05). The total effective rate in the combined treatment group was 96.43%, which was significantly higher than that in the TTNS group (82.14%, P<0.05). During treatment, one patient (3.57%) in the TTNS group experienced mild skin allergy, which recovered following symptomatic management. Conclusion The combination of TTNS and Mirabegron in drug-refractory OAB not only alleviates clinical symptoms and improves quality of life, but also shows superior efficacy in reducing urgency episodes. This approach is a safe and effective treatment option.