Surface morphology and tribological behavior of AZ31 magnesium alloys irradiated by high-intensity pulsed ion beam (HIPIB) at an ion current density of 50 A/cm2 with shot number from 1 to 10 have been investigated by using scanning electron microscope (SEM),profilometer and a ball-on-fiat tribometer.It is found that the surface morphology of irradiated sample is characteristics of cratering in local region due to a selective ablation and disturbance of the molten surface.Surface roughness increased with increasing the shot number,from an initial value of 0.11 μm to a maximal value of 0.50 μm with 10 shots.The wear test indicated that wear volume of sample irradiated with 10 shots was approximately reduced by 50 % compared with that of unirradiated sample.The improved abrasive wear resistance is due to the enhanced load-bearing capacity resulted from the increase in microhardness.Grain refinement,precipitation of β phase caused by surface remelting and rapid cooling,and the increase in dislocation density by shock waves for AZ31 magnesium alloys under HIPIB irradiation are responsible for the improved microhardness and tribological properties.