A kind of modeling for fuzzy control systems is first proposed bere, which is called modeling method based on fuzzy inference (MMFI), It should be regarded as the third modeling method that is different from two well-known modelling methods, that is, the first modeling method, mechanism modeling method (MMM), and the second modelling method, system identification modeling method (SIMM). This method can, based on the interpolation mechanism on fuzzy logic system, transfer a group of fuzzy inference rules describing a practice system into a kind of nonlinear differential equation with variable coefficients, called HX equations, so that the mathematical model of the system can be obtained. This means that we solve the difficult problem of how to get a model represented as differential equations on a complicated or fuzzy control system.