In view of the demand of different products, the concept of flexible module family is put forward，and extended analysis of module family. An optimization algorithm of flexible modular product based on least square regression model was proposed. Taking the YH30 type press as the research object，light weight optimization was carried out by using this algorithm. Under the premise of satisfying the use condition, the C column is reduced to 131 kg, which achieves the expected goal and provides references for the optimization design of the same type product.