Surface gradient nanostructure of 316L stainless steel was prepared by ultrasonic surface rolling processing (USRP). WC were implanted into the gradient nanostructure surface by using high energy ion implantation technology (HEII). First, surface characteristics of two sets of specimens were investigated through hardness distribution, sectional morphology and microstructure. Then friction and wear mechanism was discussed. Results are as follows: the ion impregnated channels were obviously increased under USRP; hardness value of the top surface of USRP + HEII specimen was increased by 57.8% and thickness of hardened layer was increased by 100% comparing to HEII specimen; wear mass loss of USRP + HEII specimen was greatly reduced compared with HEII specimen; friction and wear mechanism of HEII specimen was changed from oxidation wear to fatigue wear, while the oxidation wear and adhesion wear were the main wear mechanisms for USRP + HEII specimen as the increase of rotational speed.