Abstract: In grinding, the concept of grinding contact stiffness is too abstract and difficult to understand, which brings many difficulties to grinding applications. Based on the engineering of cylindrical grinding, a comprehensive analysis and sorting are conducted, the deformation and force of grinding related components, and clarifying the associated stiffness are ediscussed. The stiffness of the grinding machine is mainly affected by the bending stiffness of the grinding machine spindle and the tensile stiffness of the feed screw pair, and is generally relatively fixed.Grinding stiffness refers to the ability of the grinding wheel and workpiece to resist normal deformation in the grinding state, mainly depending on the grinding contact stiffness.Grinding contact stiffness refers to the normal grinding force borne by a unit of normal deformation in the grinding zone under grinding conditions, which has time-varying characteristics and is mainly related to the basic characteristics of the grinding wheel, material properties of the workpiece, working surface morphology of the grinding wheel, and grinding parameters. The main job of grinding technicians is to make reasonable use of current grinding conditions to adjust and optimize grinding contact stiffness, maintain the stability of the grinding process system, and maximize the machining capacity of the grinding machine, while meeting the grinding needs.