Objective: To explore the mediating effect of sensation seeking and the moderating effect of parenting style at cumulative ecological risk on psychosexual health in left behind adolescents. Methods: Using convenience cluster sampling, 509 left behind adolescents in 12 middle and primary schools were selected from May to July 2020. Cumulative ecological risk, psychosexual health, sensation seeking and parenting style were evaluated at baseline (T1) and 1 year follow up (T2). Results: T1 accumulative ecological risk predicted T2 psychosexual health after sensation seeking at T1 was controlled ( β=0.37, P <0.01). T1 sensation seeking predicted T2 psychosexual health after controlled for psychosexual health at T1 ( β=-0.26, P <0.01), sensation seeking played a mediating role, indirect effect accounted for 35.85% of the total effect; T1 cumulative ecological risk ×T2 parenting style had predictive effects on T2 sensation seeking and psychosexual health ( β=0.17, -0.24, P <0.01). Conclusion The cumulative ecological risk influences psychosexual health through sensation seeking, parenting style moderates the associations between cumulative ecological risk, sensation seeking and psychosexual health. Left behind teenagers with high cumulative ecological risk can cultivate good sexual psychological level by reducing high seeking traits and optimizing parental rearing styles.