The aim of the present study was structural equation modeling of the effect of constraints on satisfaction with the mediating role of sport tourists’ motivation. The statistical population consisted of all the tourists of ski resorts in Tehran province (Dizin, Shemshak, Touchal, Abali). Due to the indefinite number of the population (N=10000), 370 subjects were selected as the sample by disproportionate stratified random sampling method (due to lack of access to the number of referents to each ski resorts) using Morgan sampling table. The data were collected by the questionnaire of constraints, motivations, and satisfaction of sport tourists (2008). After it was localized and translated, its face and content validity was confirmed by 11 experts of sport tourism and its construct validity was investigated through confirmatory factor analysis (CFA). The reliability was also achieved by Cronbach’ s alpha coefficient as 0. 84, 0. 87, and 0. 79 for variables respectively. The data were analyzed for modeling with Structural Equation Model (SEM) through Lisrel software. The results confirmed the hypothesized structural relations, that is to say the constraints variable had a reverse effect both directly (-0. 19) and indirectly (-0. 44) through motivation mediator on tourists’ motivation. Besides, the motivations directly affected tourists’ motivation in a positive and significant way (1. 14). Therefore, the results and structural model allude to the fact that reducing and removing constraints increase sport tourists’ motivation and satisfaction to attend ski resorts.