Abrasive wear of alfalfa powder on the circular mould system is the main cause of the key parts failing on feed pellet machine.To improve the abrasive wear resistance of the key parts of circular mould system,the heat treatment of 45 steel was carried out by using different heat treatment process.The friction and wear behavior of 45 steel against alfalfa powder was studied on the abrasive wear test machine,the microstructure of the sample was analyzed by using metallographic microscope,and the worn surface morphology was observed by using scanning electron microscope(SEM).The results show that the abrasive wear of quenched 45 steel is dominated by microcutting wear and mechanical polishing,while plastic fatigue wear is not obvious.The wear resistance of 45 steel against alfalfa powder can be improved through rational matching of hardness and ductility when its hardness reaches certain value,meanwhile the subcritical quenching technique can obviously improve the wear resistance of 45 steel against plant abrasive compared with quenching.