OBJECTIVE To explore the influencing factors for successful detoxification in patients undergoing methadone maintenance therapy. METHODS A retrospective selection of 161 methadone maintenance therapy patients from the South Branch of Zhongshan Second People’s Hospital （including methadone maintenance treatment sites in Shiqi District， Xiqu District， Development Zone of Zhongshan City） from January 1， 2012， to January 1， 2025， was conducted as the study object. Data collected included patients’ sociodemographic information， drug abuse history， laboratory test results， medication records， etc. Patients were divided into the unsuccessful detoxification group and the successful detoxification group based on whether methadone detoxification was achieved. Univariate， univariate Cox regression， and multivariate Cox proportional hazards regression were used for influencing factor analysis， and the Kaplan-Meier method was employed for survival analysis. RESULTS Among the 161 methadone maintenance therapy patients， 96 were in the successful detoxification group and 65 in the unsuccessful detoxification group， yielding a successful detoxification rate of 59.63%. Multivariate Cox proportional hazards regression analysis revealed that age， registered residence status， age at first drug use， and duration of drug abuse were key influencing factors for successful detoxification in methadone maintenance therapy patients （P＜0.05）. Specifically， the successful detoxification rate for patients with Zhongshan local registered residence was 8.364 times higher than that for patients with non-local registered residence； for every 1-year increase in patient age， the successful detoxification rate decreased by 22.7%； for every 1-year increase in age at first drug use， the successful detoxification rate rose by 33.4%； and for every 1-year increase in duration of drug abuse， the successful detoxification rate increased by 33.5%. Survival analysis showed that the successful detoxification rate in the methadone low-dose group （≤30.8 mg） was significantly higher than that in the methadone high-dose group （＞30.8 mg） （P＝0.015）， and the successful detoxification rate in the population with Zhongshan local registered residence was significantly higher than that in those with non-local registered residence （P＜0.001）. CONCLUSIONS Age， registered residence status， age at first drug use， and duration of drug abuse are key influencing factors for successful detoxification in patients undergoing methadone maintenance therapy， and the last methadone dose may be associated with successful detoxification.