The utility model discloses a power plug capable of on/off by a bidirectional rotary cam. The utility model is characterized in that an inserting sheet is communicated with a conducting wire through a spring sheet, and the communication or the disconnection of the spring sheet and the inserting sheet is controlled by a bidirectional cam and a spring. The utility model has the advantages that the plug doesn't need to be pulled out from a socket, as long as the bidirectional cam is rotated, an electric appliance and a power can be communicated or disconnected, and the power plug has convenient use and safety, extends the service life of the electric appliance element and is suitable for various domestic appliances and other electrical devices, such as televisions, recorders, video recording players, electric fans, etc.