Previous studies on psychological displacement paradigm in diary-writing (PDPD) mainly focused on its’ pronoun characteristics and healing effects. However, the underlying psychological mechanisms of PDPD’s healing effects remained mostly unexplored. Therefore, the present study aimed to investigate PDPD’s healing effect from the perspectives of emotion peacefulness and mindfulness. Sixty-five participants wrote about their recent negative life experiences two times a week for two weeks. The results showed that participants promoted their emotion peacefulness, mindfulness, and psychological adjustments. Multiple regression analyses revealed that changes in psychological adjustments were significantly predicted by correspondent changes in mindfulness. The theoretical and practical implications of these results are discussed.