Two cemented carbides of the same nominal composition(WC-3wt%Co) were prepared by two different preparation techniques,one of which had many microgrooves on the surface and the other was compact.The influence of micro-grooves on the friction properties of WC-Co cemented carbides sliding against the GCr15 ball was studied.Friction and wear tests were also carried out using modified ball-on-disk equipment at a sliding speed of 150 mm/s and normal load condition of 5 N.The result indicated that the wear track width and the GCr15 wear volume of the compact cemented carbide are much narrower than those of the porous ones,but the quality loss of the compact cemented carbide is slightly higher than that of the porous ones.The wear scars concentrate on a certain part of the compact cemented carbide,with a lot of abrasives on their surface.For the porous cemented carbide,the wear scars distribute uniformly,with only a little abrasives on their surface.The friction coefficient of the porous cemented carbide is smaller than that of the compact cemented carbide:the porous cemented carbide is about 0.4,but the dense cemented carbide is about 0.6 with some fluctuations during the stable phase. Two cemented carbides of the same nominal composition (WC-3 wt% Co) were prepared by two different preparation techniques, one of which had many microgrooves on the surface and the other was compact. The influence of micro-grooves on the friction properties of WC -Co cemented carbides sliding against the GCr 15 ball was studied. Friction and wear tests were also carried out using modified ball-on-disk equipment at a sliding speed of 150 mm / s and normal load condition of 5 N. The result indicates that the wear track width and the GCr15 wear volume of the compact cemented carbide are much narrower than those of the porous ones, but the quality loss of the compact cemented carbide is slightly higher than that of the porous ones. The wear scars concentrate on a certain part of the compact cemented carbide, with a lot of abrasives on their surface. For the porous cemented carbide, the wear scars distribute uniformly, with only a little abrasives on their surface. The coefficient of friction of the porous ceme nted carbide is smaller than that of the compact cemented carbide: the porous cemented carbide is about 0.4, but the dense cemented carbide is about 0.6 with some fluctuations during the stable phase.