Polycrystalline Diamond (PCD) Compact is a new super-hard tool material with rapid development in domestic and abroad. It has high hardness, high thermal resistance, excellent impact toughness and small thermal expandable coefficient. Polycrystalline Diamond Compact (PDC) is widely used in petroleum geological exploration and mechanical machining, but it is confined because of its poor machining. There are only a few reports of PDC’s machining. The research object is PCD layer of PDC. Material removal mechanism of PCD and the effects of grinding parameters are investigated through tests and academic analysis in this paper. Grinding force formula is solved. Grinding tests on PCD are processed with high precision planar grinding machine. The effects of grinding parameters(velocity of wheel, depth of grinding and workpiece velocity) and characteristics of wheel(bond and granularity) on grinding force, grinding force ratio, specific grinding energy and roughness are investigated. Grinding force formula is sovled with mathematical method. The formula indicates the degree of the parameters’effects. Grinding mechanism of PCD is investigated by analyzing SEM of samples and specific grinding energy in the paper. The result shows that the removal of PCD is caused by abrasive wear, thermal-physics, thermal-chemical process, ductile distortion on high temperature and fragmentation. Abrasive wear exists all of grinding, but its effect is very slowly; Oxidation and translation of diamond is severe with high vertical grinding force and velocity of wheel; There may be ductile distortion on high temperature; Fragmentation is the most important removal fashion of PCD and it includes along-crystal fragmentation and through-crystal fragmentation. The study has a certain theoretical and practical value. But the study needs to be perfect, and it needs further research.