AbstractFeS, MoS2, WS2 and Cu2S solid films were prepared on CoCrFeNiMo high entropy alloy (HEA), and their tribological performance was tested under water lubrication. The results show that the MoS2/CoCrFeNiMo and the Cu2S/CoCrFeNiMo composite coatings provided excellent tribological properties. The MoS2 film of the MoS2/CoCrFeNiMo composite coating was not worn through at the load of 2 N, providing a reduction of 86% of friction coefficient (μ = 0.03) and 69% of the wear rate (2.68×10−9 cm3/Nm), compared to CoCrFeNiMo coating. At a higher applied load, the anti-wear performance of MoS2 film deteriorated because the MoS2 reacted with oxygen and water to form α-MoO3. α-MoO3 hinders the sliding between layers of MoS2, increasing the third-body abrasive wear of the CoCrFeNiMo coating. Unlike the MoS2/CoCrFeNiMo composite coating, the Cu2S/CoCrFeNiMo composite coating exhibited an improved friction coefficient and wear rate at all loads. This performance is a result of Cu2S reacting with oxygen and water to form Cu and CuO, protecting the CoCrFeNiMo coating from severe wear."