Abstract: Examination and analysis of cobalt-based (Co-WC-RE) alloy and YG8R cemented carbide have been made by X-ray diffraction,SEM,TEM and EDS. The results show that the addition of rare earth element exerts no effects on the lattice parameters of cobalt phase,but enables the particle size of cobalt phase to become obviously smaller and greatly improves the inhomogeneity of grain size and distribution of WC phase in the alloy. The rare earth phases which can be formed in Co-based alloy(CoWC-Y) include Y₂WO₆ rare earth oxide and Co₅Y₈ and Co₂Y intermetallic compounds.