UV-Photoelectron spectroscopy (UPS) and X-ray photoelectron speetroseopy (XPS) were used to study the electronic structure of WC, Pt and W, and high sensitive magnetometer was employed to measure the temperature dependence and field dependence of magnetic susceptibility of WC and W in the temperature range 1.5-300K. The susceptibility of W did not change with temperature, it exhibits the behaviour of Pau-liparamagnetism. But WC was entirely different, for which the Curie's law was valid. Because unpaired spins exist in WC, we made the following hypothesis: Due to the influence of carbon in WC, 5d electrons of W were no longer be itinerent thoroughly. Like Pt, part of their valence electrons became localized. The appearenee of localized electron in WC is the cause of behaving platinum-like catalystic activity.