Abstract: In a complex product development project, interdependent relationships in tasks are the main characteristics, which induce product development schedul ing to become more difficult. The design structure matrix (DSM) can resolve the problem. A new DSM model is designed based on the traditional DSM model and entr opy by the paper. According to tasks' duration and iterations, a further schedul ing model is reconstructed. The model is applied in a mechanical product develop ment project. The result suggests that the DSM model is more convenient in the r eal development process than the traditional DSM model, and is able to give more specific guidance to the development process.