A flexible modular division method was proposed to the reconfigurable machine tools （RMT）considered the influence of customer demand, the structure-function and life cycle effect. Analytic hierarchy process (AHP) was used to weight the different influence factors and the interaction among the machine tool parts and the related matrix were obtained. The fuzzy clustering method was used to operate the matrix. The control system was modular divided based on the specialty of RMT. The proposal for RMT modular division was obtained and could be used as the foundation of RMT developing. 