The three-dimensional parameterized model of the planetary reducer was established on the platform of Pro/E. Especially, the parameterized gear model was built through transforming the accurate equations of the involute and the tooth root transition curve into the expressions that can be identified by the Pro/E. Therefore, the accuracy of the model is relatively high and the method used in the paper can eliminate tooth interference effectively. Then, the three-dimensional assembly model for planetary reducer was obtained through the Virtual Assembly Technique and the Assembly Module in Pro/E. In brief, the method used in the paper has supplied a relatively accurate model for the dynamic analysis. At the same time, it can reduce dramatically research cycle and cost, and has supplied an effective development approach for the planetary reducer.