Abstract: The dynamic load of proton exchange membrane fuel cell（PEMFC）is one of the most challenging issue for fuel cell based vehicle application. It is critical to investigate the dynamic operation mechanism for appropriate PEMFC control. This study proposes a two-dimensional multi-phase PEMFC single-cell model for the simulation of internal water and gas transmission and phase transition process under different operations. Based on the test verification and grid-independent verification,the internal state changes of PEMFC under starting conditions,acceleration conditions,and emergency stop conditions are analyzed. The results indicate that the maximum PEMFC power density reaches 654.9 m W/cm2with current density 1500 mA/cm2. The PEMFC internal reaction will gradually reach balance after 10 s under starting conditions. Under the acceleration condition,the lowest water saturation interface and the water-gas phase interface have the longest duration in the cubic acceleration mode. Under the emergency stop conditions,the PEMFC remains similar to before the shutdown. This study guides the precise control of PEMFC in real applications.