Abstract: Objective To explore the mental health of drug addicts under compulsory rehabilitation. Methods Self-reporting inventory, state-trait anxiety inventory (STAI) and self-rating depression scale were used to evaluate the psychological condition of 1 031 subjects. Results The incidence of psychological problems was 53.73%. Except for interpersonal sensitivity, scores of rest items were significantly higher than the norm (all P<0.05). Hostility, STAI and paranoid ideation scores of males were significantly higher than females (all P<0.05). The lower level of education, the higher scores in somatization, obsessive-compulsive, anxiety, STAI and depression. Except for trait anxiety, there were significant differences in each dimension among addicts on different age groups (all P<0.05). The detoxification stage scores were the highest, STAI scores were getting lower with the progress of rehabilitation. Trait anxiety scores of addicts for the above-third-time and above rehabilitation were the highest. Except for hostility, phobia anxiety, paranoid ideation and psychoticism dimensions, the scores of injecting drug addicts were significantly higher than suction mouth drug users (all P<0.05). Conclusions The incidence of psychological problems of drug addicts under compulsory rehabilitation is higher and more severe than the norm. Mental health and emotion were affected by gender, age, culture level, rehabilitation stage, rehabilitation times and drug-taking patterns.