To design the mechanical structure of a dental restoration system, which working parameter should be understand clearly in first, especially the grinding force, so, the experiment using the orthogonal method is employed to find out and analysis it. The orthogonal array and range analysis were employed to study the effect of the process parameter had on the grinding force when the dental CAM system is on working, all machining parameters used in the experimental process are referring to the technical requirements for dental restoration. A high accuracy machining center, a new dental bur used only for dentistry, and a zirconia block which have excellent properties for dental restoration, are been employed to conducted the experiment, made it’s results believable. The experimental results demonstrated that the depth of cut, be the major parameter on cutting force, followed by width of cut. According to the result of analysis, the stress situation of mechanical structure of the CAM dental restoration system can be established. At the last part of this paper, a model for predict the grinding force is developed based on the experiment by means of linear regression analysis, which can be used to estimate the values of grinding force given certain grinding parameters. All of these indicated the direction for design the structure of system.