WC-Co cemented carbide balls with different cobalt (Co) content were modified by pulsed magnetic field. The effects of pulsed magnetic field treatment on tribological properties of YG6/YG8/ YG12-titanium alloy (TC4) were investigated by reciprocating friction machine and scanning electron microscope (SEM). The results show that pulsed magnetic field treatment can effectively reduce the COF of YG cemented carbides-TC4 titanium alloy friction pair. Main wear forms in the study are adhesive wear and oxidation wear. Different intensity of pulsed magnetic field changes the energy amount generated. Taking YG8 as an example, the average coefficients of friction are reduced by 20.5%, 29.7%, and 25.9%, respectively, after the 0.5T, 1T, and 1.5T magnetic treatments, compared with that without treatment. At magnetic field intensity of 1T, the average COF of YG6, YG8, YG12 cemented carbide decreased by 19.5%, 29.7%, 20.1%, respectively. With the increase of Co content, the effect of the magnetic field treatment increases first and then decreases, and the magnetic field response is the most significant when the Co content is 8%. When the pulsed magnetic field treated on cemented carbide, as an external energy, causes the Co phase change from α-Co to ε-Co, resulting in dislocation proliferation, improving the ability of cemented carbide to resist plastic deformation, strength and wear resistance, thereby improving the friction performance.