In this paper, a graphic modeling technique, switching flow-graph (SFG) technique, is applied to derive the large-signal model of three-phase PWM rectifiers. By introducing the concept of virtual switch and virtual switching function, the modeling work becomes very straightforward without complicated mathematic operations. Based on the developed model, the rectifier's transient and steady state behavior can easily be analyzed at system level. In addition, the proposed large-signal model can be implemented straightforward in MATLAB/SIMULINK environment easily for time domain simulation. Comparison of the simulation results by using the proposed SFG model with that of using PSPICE shows that both results are in close agreement. However, the execution time of the proposed SFG model is much faster than that of the PSICE. Furthermore, the simulation results by using the SFG model are closely confirmed with the experiment results.