This research proposes an integration of lean production and simulation to enhance the efficiency of process improvement. The integration model named “Lean Simulation Model” consists of five phases: Conceptualize, Investigate, Improve, Validate and Track. Step by step implementation method is described in this research. The “Lean Simulation Model” is verified by a case of Household Registration Office. Finally this model could be expanded for the application of different units with the same attribute so as to provide a model for organization to carry out the process improvements. Through the improvement of the emulation of this research, whole maximum waiting number can be reduced by 24% and maximum waiting time can be reduced by 23%.