Abstract: Poly(vinyl alcohol) (PVA) composite films were synergistically modified by adding corn starch (CS) and peach gum (PG). The effects of PVA molecular weight, different CS addition, and the PG incorporation with the same CS addition on the moisture and heat resistance of PVA/CS/PG composite film were investigated. The results show that the hydroxyl groups of CS and PG interact with PVA chains by hydrogen bonding. The crystal size of PVA in the PVA/CS/PG composite film decreases, while the crosslinking density increases. At the same time, with the increase of CS and PG content, the network mesh size of the composite film gradually decreases, and the thermal stability can be improved. The water vapor permeability test shows that as w(CS)=2% and w(PG)=2%, the water content of PG/CS/PVA composite film increases by 11.5%, while the water vapor permeability decreases by 43%.