A display device includes a detachable housing, a main body, and an interface unit. The interface unit electrically connects the detachable housing with the main body. The detachable housing includes an OSD unit for storing a plurality of OSD data; a command input unit for generating and sending signals in response to operations of a user; a processing unit for identifying operations of the user, and, if required by the operations, performing predetermined function to obtain OSD data, generating a corresponding control signal, and transmitting the OSD data and the control signal to the main body through the interface unit. The main body displays an OSD menu corresponding to the OSD data and adjusts the parameters of the display device, corresponding to the control signals.