Conventional elevated-temperature plasma immersion-ion implantation (PIII) is usually conducted at 350 degrees C, or above, to achieve a thick modified layer for practical engineering applications. In this paper, we focus on medium-temperature pill treatment of SS304 stainless steel. Two experimental protocols: high frequency, low voltage (LV); and high voltage (HV), low frequency are evaluated. The samples are characterized by Auger electron spectroscopy, glancing angle X-ray diffraction (XRD), corrosion test, pin-on-disk friction and wear test, and so on, to determine the composition, phase structure, as well as the tribological properties of the modified layer. Our results indicate that pill at 300 degrees C not only improves the mechanical properties, but also the corrosion resistance. Comparison of the wear tracks shows that 300 degrees C-PIII results in an 11-fold improvement in the surface-wear resistance. A procedure involving high implantation flux at LV is more favorable to the formation of a thick modified layer with a higher nitrogen concentration.