Abstract: Applying theory of stress and concept of synthesis health to study psychosocial factors affecting population health and their changes in one year.A cohort of 1160 workers of a factory in Jianyang city was surveyed at base-line and followed-up in one year.Their demographic character istics,life events,psychological health statuses,social supports,social function disabilities and present diseases were measured by a questionnaire and clinical examinations.By means of single factor analysis and multivariate linear regression,the main factors affecting diseases score in 1997 were occupation,age,number of positive symptom,positive symptom average score,subjective social support(R²=0.32).And the main factors in 1998 were age,SCL-90 score,positive symptom average score,degree of using social support(R²=0.345).Age,psycho logical stress level,social support etc.were the main psychosocial factors affecting on population health.