Based on Constructivist View of Learning, this article explores and analyzes the mechanism and the influencing factors of the sustainable foreign language learning abilities. It is concluded that the cognition, emotion and behavior are the internal factors of the sustainable foreign language learning abilities;and teacher, learning material and learning environment are the external factors. Learner, teacher, learning material and learning environment are the four indispensable integral factors which interact and influence each other;and thus they constitute the mechanism of the sustainable development of the foreign language learning abilities. It is hoped that this research will provide some concrete and practical theoretical ideas in developing the students' sustainable foreign language learning abilities in teaching practice.