There are many information flow's iteration, overlapping, feedback and rework in complex research and development (R&D) project design processes. In order to analysis their effect on project's duration, this paper proposes the method of combining simulation technology and Value Stream Mapping/Analysis (VSM/A) to analyze design processes. Using a Mobile Intelligent SIM Card (MISC) product development processes at an IT company as an example, the current-state value stream mapping (VSM) and Design Structure Matrix (DSM) are drawn. Overlapping concurrency are proposed for improving the design processes. After verifying the effect of presented simulation model, the dynamic simulation time data of future-state and ideal-state VSM are got. Result of simulation shows that if overlapping method are executed, the product development lead-time can be decreased significantly.