It is the trend to move to the case-based Mass Customization Products mode to fitthe customization needs in current business situation. It provides the customers the accurate cost and quotation by fast product configuration. To achieve this, the article brings out the accurate quotation based on the GBOM methodology in the case-based mass production mode, the product configuration model and the cost accumulation methodology. Finally, the whole methodology is applied to the real business and achieved good business results.