Objective To investigate the associated factors influencing the compliance to methadone maintenance treatment by analyzing the data of dropout patients in a single center.Methods The subjects were heroin addicts from Shanghai Hongkou District Mental Health Center who were on methadone maintenance treatment(MMT); they were divided into two groups: the study group(n=54) consisted of those who stopped methadone treatment within 3 months, the control group(n=107)were those who received treatment for more than 6 months. Factors such as social demographics, degree of drug dependence, methadone dose, coping style, and social support were collected, and their influences on dropout in methadone treatment were analyzed.Results Insufficient understanding, low positive response level, high negative response level, and social support were risk factors for the compliance to methadone maintenance treatment in heroin addicts.Conclusion Comprehensive interventions should be taken based on the risk factors, so as to reduce drop-out rate of MMT.