Abstract：A low carbon steel plate was treated by surface mechanical attrition (SMAT) and its surface layer structure was analyzed by XRD and TEM.The result reveals that the surface layer has transformed into nanocrystalline structure. Its friction and wear have been studied compared with the untreated sample in dry sliding by a ring-on-disc tester. Wear behavior of surface nanocrystallization of low carbon steel was discussed by surface topography. The results show that the friction coefficient of the treated specimen is markedly decreased at applied loads between 15and 75N,and its wear mass loss is reduced under 15 and 55 N. The wear scars shows that the nanocrystalline layer may reduce the effect of fatigue wear and improve the friction and wear properties of low carbon steel.