Based on study on mechanisms of high temperature N2 foam flooding, mathematical model of this technology was developed. The mechanisms of low interfacial system flooding and foam flooding were concluded in the model. Convection, dispersion, and surfactant loss due to degradation and chemical reaction were considered in describing the surfactant flow in porous media. The models were solved by using adaptive implicit method. By matching the production history of a cyclic foam injection well, we can see that this model is valid in describing the mechanisms of thermal flooding and foam flooding and the model is reliable.