To improve the sliding wear resistance of plasma sprayed Mo coating, Mo–SiC and MoO3–Al–SiC composite powders were used to prepare Mo composite coatings by plasma spraying. The results show that the introduction of SiC improved the mechanical properties and sliding wear resistance of plasma sprayed Mo coating. The reactivity of Mo and SiC was low during plasma spraying Mo–SiC composite powder. The thermite reaction for MoO3 and Al was not conducive to the densification of the composite coating prepared by MoO3–Al–SiC composite powder, but improved the reactivity of in-situ generated Mo and SiC, and the Nowotny phase Mo4.8Si3C0.6 was observed in the coating. The coating prepared by Mo–SiC composite powder displayed better mechanical properties and sliding wear resistance than that of the coating prepared by plasma spraying MoO3–Al–SiC composite powder. The coating obtained by Mo–SiC composite powder revealed a combination of adhesive wear, abrasive wear and oxidation wear.