Modularization is an effective tactics in designing complex products.  Not only the internal factors, such as the separability of the rules for system designs and “No Out-of-Control” strategy carried out by designers, militate against the use of modularization in designing complex products.  Multi-agent model for complex product design systems was built and simulated.  Relationship between the dynamic characteristics of customer demands and the sale volume of products manufactured by modularization or semi-modularization manufacturer or nonmodularization modes was analyzed.  The adaptation of different modes of modularization in complex product design systems to the dynamic customer demands was also discussed.