A simplification method of complex nonlinear static characteristics of fuel cell is presented on the basis of automatic piecewise linear fitting method. This method can automatically give the piecewise linear fitting simplified model which can meet the predefined error requirement and change the number of linear subsection by adjusting the error limitation， thus improves the simulation speed while ensuring the simulation precision. It is also suitable for other distributed sources with nonlinear static characteristics. The validity of this method is proved by comparison and analysis between the detailed model and the simplified model.