Based on the Expectancy-Value Theory (EVT), this study examined the interactive relation between expectancy of success and attainment value, and how they predicate students' Foreign Language (FL) performance via behavioral engagement. Self-report data were collected from 522 Chinese non-English majors aged 18 to 22 years in their sophomore year. Results of structural equation modeling indicated that expectancy of success and attainment value interacted in predicting Chinese sophomores' FL performance. The expectancy of success had both direct and indirect effects on FL performance when investigating the mediating role of behavioral engagement. Both theoretical and practical implications are discussed.