Objective To systematic review the international interventions on mental health of involuntary migrants, and evaluate the effects of different interventions. Methods We searched 10 international electronic databases and 3 grey literature databases to November 2008. Websites of relevant organizations and Google were searched for any missing information. Research papers that reported describing or evaluating any interventions on preventing and treating mental health problems of involuntary migrants were included. Two reviewers independently screened, appraised and extracted the data, disagreements were resolved by discussion. Implemented interventions were summarized and analyzed by qualitative synthesis method. As there was heterogeneity in the type of interventions, study design, and outcomes, the study results were not pooled statistically in meta analysis. Results Of the 35 studies included in the analysis, 16 studies aimed to describe intervention strategies, while 19 studies were to evaluate effectiveness of interventions. The targeted population were mainly refugees and asylum seekers caused by the war, violence and other tortures, while only one study targeted at reservoir migrants. All the psychological interventions were divided into prevention intervention and treatment intervention. The main interventions include: integrated psychological intervention, group treatment, cognitive behavior therapy, testimony, narrative exposure therapy, supportive counseling service, family support and therapy, etc. Of which, integrated psychological interventions are the most common intervention. Most of the studies evaluating effectiveness are observational studies, while only six are controlled trials. The results of most evaluation studies show that the implemented psychological interventions have positive impact on mental health of involuntary migrants. Conclusions There are limited intervention studies on mental health of involuntary migrants, and evaluation studies are lack of rigorous design. More research especially preventive intervention study is required. High-quality trials with large sample and rigorous design are needed to evaluate the most effective psycho-interventions for different groups of involuntary migrants.