In order to improve the wear resistance of debris-ejecting blade of driller, cemented carbide welding coatings were prepared by arc-welding technology. The abrasive wear behavior and wear mechanisms of cemented carbide welding coatings were researched under both dry and water friction conditions. The research results show that the wear rates of the coatings increase with the increase of loads and sliding speeds. The influence of sliding speeds on wear rates of the coatings becomes intense as the increase of loads. The wear rates of the coatings under water friction conditions are bigger than those under dry friction conditions. The main wear mechanisms of the coatings are micro-cutting and multi-plastic deformation wear of matrix metal, and micro-cracking and brittle fracture as well as spalling of WC particles.