A switching device includes multimedia input interfaces for respectively receiving multiple multimedia signals, a switching unit electrically connected to the multimedia input interfaces, a multimedia output interface, an electrical characteristics modulator, and a controller. The switching unit outputs a selected multimedia signal according to a first control signal. The multimedia output interface includes a multimedia signal terminal for outputting the selected multimedia signals and a non-signal terminal. The electrical characteristics modulator changes an electrical characteristic of the non-signal terminal according to a second control signal. The controller is controlled to generate the first and the second control signals through a video switching method whereby the electrical characteristics modulator changes the electrical characteristic of the non-signal terminal thereby increasing compatibility between the switching device and a multimedia output device.