It has been found that there was an interrelation between free will belief and well-being, but the causal direction between them has not been determined yet. The present study applied a cross-lagged design to test the causal relation between free will belief and two different kinds of well-being (hedonic and eudaimonic) among Chinese undergraduates. The results showed that free will belief could predict life satisfaction and flourishing but not positive and negative affect two months later. Our investigation provides evidence for free will belief as a positive predictor of cognitive evaluation to life and human functioning.