Abstract: Objective To analyze the prevalence rate and distribution characteristics of serious mental illness in the residents of Nanming district of Guiyang city, and to provide a basis for prevention and rehabilitation of major mental illness in communities.Methods A survey on serious mental diseases was carried out among permanent community residents in Nanming district of Guiyang city with cluster sampling and case-finding.International Statistical Classification of Disease and Related Health Problems, 10th Revision(ICD-10)and Chinese Classification and Diagnostic Criteria of Mental Disorders, 3th Revision(CCMD-3)were adopted as diagnostic criteria in the survey.Results Totally 1 289 serious mental disease patients were identified, with an overall prevalence rate of 2.237‰, and the prevalence rates of 1.311‰ for schizophrenia and of 0.885‰ for mental retardation accompanied with mental disorders.The prevalence of serious mental illness in the males(2.883%) was higher than in the females(1.774‰), with a statistically significant difference(χ²=74.498, P=0.000);the prevalence rate of serious mental illness in rural residents(3.246‰)was higher than that in urban residents(2.214‰)and the difference was statistically significant(χ²=26.669, P=0.000).The severe mental illness was more prevalent among the residents aged 36-45 years, acounting for 30.11% of all cases.Among the patients diagnosed, 45.31% were laid-off employees or the unemployed and 56.09% were unmarried.Conclusion Schizophrenia, mental retardation accompanied with mental disorders, and epilepsy are major diseases for serious mental disease preveation among residents in Nanming district of Guiyang city.