Abstract: With the development of Mass Customization (MC) mode, the degree of customization of products and delivery time is affecting the cost obviously, and the three facts made a tight coupling of the "mysterious triangle". Therefore, the researching on the cost of customized products is more popular than before. The research of this paper is the cost of products customized which based on the level of parts, through getting parts classification for RTO product base on cost estimating features, studying on fees of different types of parts which generate in different process of produce, especially for time, to build a product cost model through estimating the different kinds of cost of parts for the valuation of customized products in a timely manner, and also assist to decision for enterprise.