Abstract: CoCrMo alloy was prepared by vacuum induction melting technology, its microstructure, phase composition, corrosion resistance and tribocorrosion behavior were studied. The wear-corrosion mechanism and wear-corrosion resistance mechanism of the alloy in piped water, deionized water and different concentrations of calf serum were analyzed in detail. CoCrMo alloys were composed by γ-Co and ε-Co, and their microstructure consisted of equiaxed crystals with sizes ranging from 7.1 to 304.7 μm. CoCrMo alloy had better corrosion resistance in deionized water and piped water compared with in calf serum solution. This was because the albumin in the calf serum solution promoted the dissolution of Mo element in CoCrMo alloy. The average friction coefficient of CoCrMo alloy in calf serum solution (0.12~0.20) was lower than that in deionized water and piped water. This was because calf serum dissolved at the friction interface to form a lubricating film, which could improve the stability of the friction coefficient while significantly reduced it. Wear and corrosion had a mutually reinforcing effect, with wear promoting corrosion more than corrosion promoting wear. Due to the mutual promotion of wear and corrosion, the wear rate of CoCrMo alloy in calf serum solution was more than 1.5 times that in deionized water. The mechanical wear was the main reason for the material loss in all tribocorrosion tests.