A data processing device with multiple hardware systems and a switching method thereof are provided. The device comprises a first hardware system, a second hardware system, a shared device and a switcher, wherein the first hardware system is connected to the shared device through the switcher, and includes a first inquiry module for inquiring information on applications currently executed in the first hardware system so as to obtain an inquiry result, a first control module for triggering the first inquiry module to perform inquiry when it is required to switch from the first hardware system to the second hardware system, and a first communication module for transmitting the inquiry result to the second hardware system; and the second hardware system includes a second communication module for receiving the inquiry result, a second control module for, in accordance with the inquiry result, activating corresponding applications in the second hardware system so as to generate a first message, and transmitting the first message to the first hardware system through the second communication module; wherein the first control module instructs the switcher to switch the shared device into connection with the second hardware system when the first message is received by the first hardware system through the first communication module.