The fuel cell is an important distributed source. An appropriate simulation model is of great significance when studying its dynamic characteristics under various disturbances. With the solid oxide fuel cell（SOFC） as an example， a detailed dynamic model of SOFC and two simplified models that neglect the variation of gas partial pressure are discussed. Then the three models are applied in the simulation of an SOFC-based distributed generation system under different operation and fault conditions. By comparing the simulation results， the applicable application ranges of the three models are given.