Introduction: Psychosomatic disorders are among the problems caused by stressful factors of life. The aim of this study was to developing structure model of psychosomatic disorders based on cognitive ability, morningness-eveningness types and brain/behavioral systems mediated by perceived stress in women with chronic pain in Ahvaz. Methods: The present study is descriptive-correlational. The statistical population of the study includes all women with chronic pain who were treated in medical centers in Ahvaz in 2020. The statistical sample consisted of 200 women with chronic pain in Ahvaz who were selected by purposive and available sampling method. Participating women had more than 3 years of physical pain that did not improve with medical treatment and was diagnosed with psychosomatic disorder. In order to collect data from the demographic questionnaire, the "psychosomatic complaints" subscale, of “, Mental Health Measurements", "Nejati Cognitive Abilities Questionnaire", “, Horne & Ö, stberg Morningness-Eveningness Types Questionnaire", “, Brain/Behavioral Systems Questionnaire”,and “, Perceived Stress Scale”,were used. The validity of the instruments was based on previous studies and the reliability was determined by internal consistency by calculating the Cronbach's alpha coefficient. Data analysis was performed in SPSS. 24 and Amos. 24. Results: The pattern of structural equations showed that cognitive ability and perceived stress are directly correlated with psychosomatic disorders (β, =0. 33). Also, cognitive ability (β, = 0. 40), types of circadian times (β, =-0. 16) and behavioral inhibition (β, =0. 29) are correlated with psychosomatic disorders through perceived stress. Therefore, the modified model fits the data. While the behavioral activator component is not directly related to psychosomatic disorders either indirectly or through perceived stress. Conclusions: Psychosomatic disorders are predicted through cognitive ability, different types of circadian times, and behavioral inhibition mediated by perceived stress. It is suggested that with effective training and treatment of perceived stress, help to improve the symptoms of psychosomatic symptoms and chronic pain.