Abstract: The SOFC (solid oxide fuel cell) and its grid-connected system is established base on Matlab/Simulink, and the external characteristics of SOFC power systems is researched; then a equivalent model of SOFC power generation system is proposed from the perspective of external characteristic equivalent fitting and ignoring the reactive power of the SOFC generation system. This equivalent model has a simple structure, less parameters, can be identified easily. It can fit the external characteristics of SOFC power systems effectively in the case of large disturbance and continuous small disturbance of power system, compared with other equivalent models, this model can simulate the limit of the fuel cell’s output; the synthesis load model multiplied with equivalent model is used to fitting the characteristics of power synthesis load containing the SOFC power systems, examples show that this generalized load model can describe the load characteristic of distribution network with fuel cell power generation system, and identification result of it’s parameters are stability.