The fretting wear-resistant properties of ion-sulphuration+shot-peening and shot-peening+ion-sulphuration duplex-treated coatings on 1045 steel substrate were investigated. The results show that the fretting wear-resistance of shot-peening+ion-sulphuration coating was better than that of the ion-sulphuration+shot-peening coating. The fretting wear process of the duplex-treated coatings in the gross slip regime could be described as the sulphuration coatings playing an important lubricating role in the incubation period. Then a series of changes took place continuously and alternatively on the contact surfaces, including adhesion, material transfer, oxidation, delamination of the oxide layer and degradation. In the last stage, the trapping, pulverization and elimination of debris restrained the adhesion between the contact surfaces and led to a decrease in the friction coefficient.