Abstract: Objective To describe current prevalence and distribution of all types of mental disorders among adult residents in Liaoning province and to provide evidences for developing a provincial mental health plan.Methods Stratified multistage cluster randomization was used to recruit 24 000 urban and rural residents aged 18 years and above in 7 municipalities.All the participants were screened with the expanded version of the General Health Questionnaire (GHQ-12) and assigned into one of the three groups at high,moderate,and low risk of having a mental disorder.Then,based on the criterion of Diagnostic and Statistical Manual of Mental Disorders-4th Edition(DSM-IV),the diagnostic examination was performed by psychiatrists among 100%,40%,and 10% of the participants of the groups with high,moderate,and low risk of having a mental disorder using Structured Clinical Interview for DSM-IV Axis I Disorders-Patient Edition (SCID-I/P).The survey was carried out between October 2014 and June 2015.Results Of the residents,82.22% (19 733) completed the survey.The adjusted current (in the previous one month) prevalence rate of any mental disorder was 14.05% (95% confidence interval:13.57%-15.47%).The overall prevalence rate of mental disorders was higher in the males (15.46%) than in the females (12.93%),and slightly higher in rural participants (14.83%) than in urban participants (13.04%).Among all the participants,the three most common mental disorders were affective disorder (4.57%),anxiety disorder (3.63%),and substance use disorder (2.88%).Alcohol use disorder (2.86%) and major depression disorder (2.39%) were the most prevalent specific mental disorders.Conclusion The current prevalence rate of mental disorders is relatively high among adult residents and mental disorder has become a major public health problem in Liaoning province.