Abstract: In OEM-OBM mixed operation, the contract manufacturer provides production service to the outsourcer and develops its own brand products at the same time. Replacing OBM products' key parts with the outsourcer's is one of the most useful strategies to improve the quality and customer acceptance of OBM products. Accordingly, the effect of parts replacement in consumer choice behavior is analyzed firstly. Then the OEM-OBM Mixed Assemble-to-Order revenue model considering parts replacement is constructed. The model analysis and numerical simulation show that the OBM product demand increases as the replacement rate is added; and that the price of the OBM product are positively correlated with the parts replacement rate in some situations. If the replacement rate is not constrained, the contract manufacturer could gain a more market share with higher rate of parts replacement.