A longitudinal study was conducted to assess changes in and contributing factors of learner belief for a sample of 70 Chinese foreign language learners. Foreign language proficiency and learner factors such as learner belief and learning strategy were measured four times at approximately fifty-day intervals. The results show that there were significant changes in self-efficacy belief, belief about learning difficulty and belief about learning strategy. The major contributing factors to changes in self-efficacy belief include learning strategy, effort, foreign language anxiety, motivation and foreign language proficiency. Meanwhile, learning style, learning strategy and foreign language anxiety have significant effects on changes in learner belief about learning strategy.