A high wear resistant TiC/Co/Y2O3 composite coating was synthesized on the surface of AZ91D Mg alloy by plasma transferred arc (PTA) coating process. The results showed that the major phases present in the coating were TiC, Al2O3, Y2C3, Y2Al, TiCo3 and Co2Ti. The coatings had a sound metallurgical bonding to AZ91 Mg alloy substrate. The maximum average surface hardness of TiC/Co/Y2O3 composite coated layer was found to be around 3374 HV0.05, which is about 49 times higher than that of AZ91D Mg alloy (68 HV0.05). The wear rate of the coatings was 8.48 × 10-8 g/N-m, which was reduced about seven times as compared to AZ91D Mg (58 × 10-8 g/N-m). It was concluded that the wear resistance of TiC/Co/Y2O3 composite coating was enhanced as compare to the AZ91D Mg alloy. This type of TiC/Co/Y2O3 coating may increase the application of AZ91D Mg alloy in the automotive industries for manufacturing of tribological components.