The work aims to improve hardness and wear resistance of 316L stainless steel. Assisted by hollow cathode DC arc, 316L austenitic stainless steel was plasma nitrided (PN), plasma nitrocarburized (PNC) and plasma nitrocarburized + plasma nitrided (PNC+PN) at 400 ℃ and 2 Pa. Microstructure, morphology, phase, mechanical property and corrosion resistance of the treated samples were characterized with Lycra microscope, scanning electron microscope (SEM), X-ray diffractometer (XRD), Vickers hardness tester, 3D morphology meter, pin-on-disk wear instrument and electrochemical workstation. Physical properties of the treated samples were analyzed with microharness tester HV-1000 and CSM micro-nanoindentor. Assisted by the hollow cathode DC arc, growth rate of diffusion layer could exceed 3 mm/h by adopting the three processes. Compared with the 316L stainless steel substrate, surface hardness of PNC+PN treated sample increased by more than 3 times, corrosion current density decreased by nearly 50% in 3.5%NaCl neutral electrolyte. PNC treatment and PNC+PN composite treatment can obtain higher diffusion layer thickness and surface hardness. The higher the content of C and N in the layer is, the higher lattice parameter of the phase constituting the layer is, the greater the slip band density in the layer is. Low temperature and low pressure plasma arc-assisted ion diffusion can not only improve surface hardness of 316L stainless steel effectively, but also enhance its corrosion resistance.