This paper discusses how to introduce extraordinary optical transmission，which is one of frontiers of optical research，into single slit diffraction experiment demonstrated for University Physics class. Based on numerical simulation，the diffraction phenomenon of nano scale singleslit and micro scale single-slit are compared under Fraunhofer diffraction condition. It is pointed out that such anomalous diffraction charateristics of nano scale single slit originates from the strong interaction between light and matter in nanoscale，which is not significant in the Fraunhofer diffraction from micro scale single slit. Finally，the design of the demonstration experimental system for class is discussed.