The invention relates to a sales practical training cabinet of a practical training chamber of a power supply administration and an application method of the sales practical training cabinet. The cabinet comprises a computer, a bench body, a PT, a CT secondary wire connection terminal, an imaginary load power supply, a wire connection switch box module, a phase position voltammeter, an electricityleakage protection module, a speech timing module, a voltage loop short circuit and current loop opened circuit protection indication device, a TV, a TA simulation wire connection terminal bar and acomputer simulation system controller. The invention also provides an application method of the sales practical training cabinet.