Aging is a dynamic concept in today’s world, and the quality of life should be taken into consideration as the elderly population grows. Therefore, the purpose of this study is to investigate the simple and multiple relationship between psychological, spiritual and social capital with clinical symptoms of elderly people living in nursing homes of Chaharmahal and Bakhtaran province. To this end, 200 elderly people were selected by simple random sampling method and responded to the questionnaires. The research tools include the Luthans’ Psychological Capital Questionnaire (PCQ), Kings’ Spiritual Capital, Onyx’s Social Capital, and Clinical Symptoms. The results show that there is a reverse and significant correlation (at a level less than 0.01) between psychological, spiritual and social capital with physical impairment, obsession, hypersensitivity in interpersonal relationships, depression, anxiety, aggression, phobia, paranoia, psychosis and total score of clinical symptoms. Furthermore, the results of regression analysis show that psychological capital predicts mental health in all aspects of the clinical symptoms of the elderly, while spiritual and social capital are out of the equation. Overall, psychological capital accounts for 34% of the variance in the health of the elderly. And of its four components, hope, optimism and resilience are respectively the predictors of mental health, which together account for 33% of mental health variance. Therefore, based on the results, it can be said that planning to increase psychological capital such as hope, optimism, resilience and self-efficacy during the young and middle ages, can help reduce the possibility of all types of mental disorders and thus increase the mental health of people during the old age.