In practice a MOSFET is anti-parallel with a diode. In the paper there is a method how to build its model. The model applies for the MOSFET works as a power switch. The model consists of two capacitors, a voltage-controlled switch and a diode. There is an example for the model building. The circuits including the model are simulated. The results prove that the electrical data of model equals basically its actual data. The model can help electrical engineers design circuits which uses MOSFET as a power switch. The model built only need the data of its manual. The merit is very suitable for electrical engineers.