The study is based on conceptual design to build a process of integrating creative design for customers’ demand systematically. The process effectively combines the theories of QFD (Quality Function Deployment), human factors engineering, value engineering and TRIZ (Theory of Inventive Problem Solving) to solve the contradiction and restriction. It can find out the questions that need to be improved and reduce the frequency of design. This study will apply the process on light mechanic gun (LMG) interface design to make the LMG system module systematic, comfortable and easy-disassembling as well as provide reasonable references of purchase and research on new LMG in the future.