The helix flute grinding was important to machine a complex revolving tool. The geometric parameters (especial its rake angle, flute depth and flute width) have essential effect on the performances of the tool. Using the 6UPS parallel grinding machine developed from BEIHANG, especially after analyzing its special machining and structure features, this paper gave general analysis to all factors which will influence the flute shaping. According to the moving relationship between grinding wheel and the tool, a simulation modeling system was established. This system could be adopted to optimize and quantitative design that influence parameters deeply. The parameters refer to the grinding wheel defluxion, the grinding wheel thickness, the grinding wheel offset position along the X direction, and the flute depth. Experiments were carried out to verify the influence results.