This study examined the differences in expectancy and value beliefs of individuals in different stages of exercise behavior's, based on the transtheoretical model (Prochaska & DiClement, 1982) and Eccles' expectancy-value theory (Eccles et al., 1983). Measurements of this research were the revised Behavior Stage Scale (Lin & Lu, 2002), the Expectancy and Value Beliefs Scale (Liao, 2007), and Physical Activity Scale (Liu et al., 2003). Five hundred and sixty three students aging form 9 to 19 (M=14.19, SD=3.04) completed the questionnaires. The one-way ANOVA was used to analyze the differences in expectancy and value beliefs of students in different exercise behavior stages. The results showed that students in different exercise behavior stages were significantly different in scores of ability expectancy, psychological cost of failure, expectancy cost from significant others, and task value, but no difference was found in required efforts. The data partially supported the validity of utilizing expectancy and value belief to describe the psychological differences of individuals in different stages of exercise behaviors, but more research is expected.