A mass transfer model is built up for metal ion implantation at elevated temperatures based on the transport of ions in solid and the radiation enhanced diffusion theory, and the effective formation heat model is built to predict the intermetallics formation during the ion implantation by introducing. The surface modification of AZ31 magnesium alloy by Al ion implanting at elevated temperature is carried out in a MEVVA 80-10 ion implantation system. The concentration-depth profiles of implanted Al and the microstructure of implanted samples are analyzed by Rutherford backscattering spectrometry and x-ray diffraction, respectively. The calculated concentration-depth profiles and the predicted formation of Al₁₂Mg₁₇ intermetalics are consistent with the measurement results. The AZ31 magnesium alloy samples implanted with an implantation dose of 6×10¹⁶ ions·cm^-2 have the highest corrosion potential of －1 180 mV (SCE)and pitting corrosion breakdown potential of －480 mV (SCE). Their passive current density is reduced correspondently by about one order that of the original sample. The worn grooves observed on the Al ion implanted samples at elevated temperature is narrow with a reduced wear rate of about 20 % that of the original sample. The Al ion implantation into AZ31 magnesium alloys at elevated temperature improves significantly performance of anti-corrosion and wear-resistance.