The invention relates to an embedded electric energy measuring method and an application extension method of a high voltage electrical switchgear and belongs to the field of intelligent high-voltage electricity. A high voltage intelligent electric energy measuring unit comprises a high-voltage current sampling device, a high-voltage voltage sampling device, an electric energy measuring module, a source unit and a wireless transmission module. The embedded electric energy measuring method and the application extension method are characterized in that the components of the high voltage intelligent electric energy measuring unit are respectively embedded inside the high voltage electrical switchgear to acquire an mA-grade standard current measuring signal proportional to the current of the switchgear and an mV-grade standard voltage measuring signal proportional to the voltage of the switchgear; and the mA-grade standard current measuring signal and the mV-grade standard voltage measuring signal are input into the electric energy measuring module to complete signal processing and electric energy measurement. The application of the high voltage electrical switchgear to pre-paid management and intelligent control is extended by the method. According to the invention, the electrical isolation of a high voltage switch is utilized, the manufacturing materials are saved, the occupied space is reduced, the measurement cost is greatly reduced, the embedded electric energy measuring method and the application extension method of the high voltage electrical switchgear are widely used for the high voltage electric energy measurement, the high voltage electric energy monitoring and the intelligence of the high voltage electrical switchgear, the safety operation coefficient is improved, and the functions of intelligence, electric larceny prevention, data acquisition and transmission are increased.