Abstract: High carbon equivalent gray cast iron was treated by ferritic nitrocarburizing at low temperature. The sliding tribological properties of untreated high carbon equivalent gray cast iron and high carbon equivalent gray cast iron after nitrocarburzing were investigated. The results show that the wear model of untreated high carbon equivalent gray cast iron was adhesive wear with mild abrasive wear under low load and with severe abrasive wear under high load. The wear model of ferritic nitrocarburized high carbon equivalent gray cast iron was mild adhesive wear under low load, in addition to the adhesive wear accompanied by mild abrasive wear under high load.