The invention discloses a dynamic assembly CAD model global symmetry identification method based on rules, comprising the following steps: 1, classifying and dividing all the parts into a plurality ofconsistent part sets; 2, identifying symmetry of each part set, and marking each identification result; 3, setting part set sorting rules, and sorting the part sets; 4, calculating intermediate modelsymmetry by utilizing combination validation rules and kinematic pair rules; and 5, recursively calling the step 4, and carrying out combination validation on the intermediate model symmetry until global symmetry of the whole dynamic assembly model is determined. The method disclosed by the invention is specific to dynamic assembly CAD model global symmetry identification and designs the combination validation rules and the kinematic pair rules, and the rules are designed by fully utilizing static information and dynamic information of the assembly model and through geometric reasoning. Densesampling can be effectively avoided from being carried out on a motion period by utilizing the rules, so that dynamic symmetry identification accuracy and efficiency are greatly improved.