A unified device management method and system for unified management of a fixed and mobile device includes a command execution controller which receives a device management command, sends a query message to the device, receives a response message transmitted by the device, creates a command execution policy based on the settings contained in the response message, and executes the device management command according to a policy, the device which generates and sends the response message to the command execution controller according to user inputs, and a remote access server which connects the device and the command execution controller by using a remote access protocol.