Student engagement is believed to be a major predictor of academic achievement and has become the core concept of educational psychology, but in foreign language learning, there are rare studies concerned. A structural equation modeling（SEM） was established based on the literature review of previous studies on L2 motivation, anxiety and student engagement. SEM shows that all of the three aspects of English self system have positive effects on student engagement; the ideal self and ought-to self have positive effects on anxiety while the learning experience has a negative effect； anxiety has a negative effect on learners’ student engagement.