Objective To investigate the psychsocial factors of some psychosomatic diseases.Methods 1500 patients with psychosomatic diseases,including primary hypertension,coronary heart disease,duodenal bulb ulcer,functional dyspepsia,hyperthyroidism,diabetes,migraine,recurrent aphthous ulcer,disturbances syndrome of temporo-mandibular joint,chronic urticaria,eczema,menopausal syndrome,allergic rhinitis,obesity and bronchial asthma,with every 100 patients for each disease were sampled as the subjects.The EPQ,SCL-90,SAS,SDS,the Social support Rating Scale(SSRS),and the Defense Styles Questionnaire(DSQ) were used to assess the related psychosocial factors.Results Patients with psychosomatic diseases got significantly higher EPQ-N score,SAS and SDS score,and lower scores of social supporting than the control group.The patients used much more defense ways of repression,avoidance and complaining.Conclusion Psychosocial factors,such as personality,social supporting and defense styles played important roles in the onset and development of psychosomatic diseases.