Abstract: For the purpose of improving the efficiency of modeling and optimization of complex product development process, a method based on design structure matrix and Sys ML is presented. Firstly, this method undertakes requirements analysis for complex product through Sys ML and obtains the preliminary system design scheme. The product development process is hierarchically decomposed and optimized with the design structure matrix method in order to reduce the iterative design activities. Secondly, the development process is graphically modeled and represented by Sys ML, which contributes to the guaranteeing of consistent and reusable process models and improves the accuracy and efficiency of process modeling. Finally, an example of engine is demonstrated to verify the effectiveness of the proposed method.