To extend the safety service life of aviation TC4 alloy, the composite coatings of TC4 + Ni-MoS 2 + WC + xY 2O 3 ( x = 0, 1, 2, 3, 4 wt.%) were prepared on TC4 by coaxial powder feeding laser cladding technology. The results showed that all the coatings had the same generated phases which mainly consisted of TiC, Ti 2Ni, Ti 2S, matrix β-Ti, and unfused residual WC. Y 2O 3 formed co-dependent growth relationships with TiC, Ti 2S, and Ti 2Ni. Meanwhile, TiC-Ti 2S, TiC-Ti 2Ni, and Ti 2S-Ti 2Ni coherent composite structure phases were effectively synthesized in all the coatings. With the increase in the Y 2O 3 content, the exposed area of the matrix increased and other phases refined progressively. When the Y 2O 3 content in the coatings were 3 and 4 wt.%, the degree of phase refinement in the coatings was consistent and the phases grew along grain boundaries, but microstructure segregated in the 4 wt.% Y 2O 3 coating. The microhardness of all the coatings was higher than that of TC4 and decreased with the increase in the Y 2O 3 content. Higher friction coefficients and lower wear rates both appeared in all the coatings than in the substrate, and they presented a trend of decreased first and then increased with the addition of Y 2O 3, in which the 3 wt.% Y 2O 3 coating had the lowest friction coefficient and optimal wear resistance. The research found that the Y 2O 3 could not change the types of phases in the coatings and could serve as a heterogeneous nucleation center for the refinement of the TiC-Ti 2S-Ti 2Ni coherent structure phase. Meanwhile, except for the matrix phase, Y 2O 3 could attract other phases to pinning on the grain boundaries of the coatings. The content of Y 2O 3 was negatively correlated with the hardness and wear resistance of the coating and it had the optimal tribological properties with the moderate amount of Y 2O 3. The wear mechanism of all coatings was abrasive wear.