Based on previous finding that self-esteem predicts meaning in life, this study introduced locus of control and positive emotion as mediators, aiming to explore the predicting mechanism of self-esteem on meaning in life from cognitive and emotional perspective. Self-esteem, locus of control, positive emotion and meaning in life of all the participants were measured by Self-esteem Scale, Locus of Control of Behavior Scale, Positive Affect and Negative Affect Scale, Meaning in Life Questionnaire before the experiment. Then expressive writing intervention was performed to manipulate the participants’ level of self-esteem. At last, all the participants finished the measurement of locus of control, positive emotion and meaning in life again. Repeated measure ANOVA was performed to test the effect of experimental manipulation of self-esteem on locus of control, positive emotion and meaning in life, and hierarchical multiple regression and Boostrap were utilized to test the mediating effect of locus of control and positive emotion on self-esteem and meaning in life. The result indicated that experimental manipulation of self-esteem could significantly affect locus of control, positive emotion and meaning in life. Furthermore, positive emotion and locus of control were mediators between self-esteem and meaning in life.