Objective: One of the most important social factors that have been consistently identified as a predictor of healthy aging is marriage satisfaction. Therefore, the purpose of the present study was to investigate the effect of social support on marital satisfaction with mediating role of emotional loneliness and physical activity. Method: This study was descriptive and correlational based on structural equations. The statistical population consisted of all the elderly in the care centers of Shahrekord and Farsan in 2019, among whom 180 individuals were selected randomly. The participants filled out research instruments including Relationship Assessment scale (Hendrick, 1998), Perceived Social Support scale (Zimet, et al., 1988), Adult’s Social and Emotional Loneliness scale (DiTommasso, et al., 2004), and Leisure-time Activities scale (Godin, 1985). Structural equation modeling (SEM) was used through SPSS (version 23) and AMOS (version 23) software to analyze the data. Findings: The results demonstrated direct effect of social support, emotional loneliness and physical activity on marital satisfaction (p <0.001), and indirect effect of perceived social support on marital satisfaction through emotional loneliness and physical activity (p <.05). Conclusion: The SEM results of the current study support the proposed model which explains the interrelationships between perceived social support, loneliness, physical activity, and marital satisfaction. According to the findings of the present study, it is suggested to pay more attention to the variables of social support, emotional loneliness and physical activity in order to improve the marital relationships of the elderly. The findings of this study can help psychologists and other caretakers create more effective family matter programs for the older generations to enhance their marital satisfaction.