WC-Co cemented carbide balls with different cobalt (Co) contents 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 SEM. The results show that pulsed magnetic field treatment can effectively reduce the coefficient of friction (COF) of YG cemented carbides-TC4 titanium alloy friction pair. Main wear forms are adhesive wear and oxidation wear. Different intensities of pulsed magnetic field change the energy amount generated. Taking YG8 as an example, the average COF are reduced by 20.5%, 29.7%, and 25.9%, after the magnetic 0.5, 1, and 1.5 T treatments, respectively, compared with that without treatment. At magnetic field intensity of 1 T, the average COF of YG6, YG8, YG12 cemented carbide decreases by 19.5%, 29.7%, 20.1%, respectively. With the increase in 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 8wt%. As an external energy, the pulsed magnetic field used on cemented carbide causes the Co phase from α-Co to ε-Co and thus results in dislocation proliferation; as a result, the ability of cemented carbide to resist plastic deformation is improved, and the corresponding macro-phenomenon is an increase in strength and wear resistance, so that the friction performance is finally improved.