CoCrAl-B4C coating was successfully deposited by air plasma spray technology. The coating micro-structure, microhardness, bonding strength, thermal shock and tribological performance were analyzed. The results show that the microhardness and bonding strength of CoCrAl-B4C coating are 980HV0.2 and 17.5 MPa respectively, and no failure occurs after ten time’s thermal shock tests at 900℃; The lower friction coefficients of CoCrAl-B4C coating appear when the coating in water vapor atmosphere or preheating treatment at 700 ℃, which are attributed to the formation of B2O3 and H3BO3 lubricating phases on the worn surface.