Abstract: A bill of material(BOM) model is constructed on the basis of polychromatic graph to increase the correctness, integrity and consistency of BOM data maintenance.By changing the object state,explicit or hidden,the model is mapped to application BOM.Structural,semantic and general relations between the proposed model and the application BOMs are discussed.Based on the designed BOM,parts quantity matrix is established to calculate the quantity of the self-made parts and the purchased parts.A case study shows that the presented polychromatic-graph-based BOM model is easy to manage, extend and change,and is suitable for distributed BOM management.