Objective To study rapid design method of coater in mass customization. Methods Case-based reasoning technology was applied in the coater design process. Case-based reasoning principles and key technologies, coater cases presentation and the method to retrieve and amend were studied. Coater cases libraries were built and applied by database cases representation. The nearest neighbor method was used for retrieval of coater cases, and the method of transformation programs based on the framework was used to amend the most similar case. Results Based on the Pro ENGINEER 5.0 platform, case-based reasoning coater rapid design system was developed and resources were integrated and reused. Test revealed that the design efficiency of coater was improved by 30% . Conclusion With case-based reasoning technology applied to the coater design, the efficiency of product design was improved, the cycle of product development was shortened and the market competitiveness of enterprise was enhanced.