An IP camera includes a camera unit for picking up images of a target object; a wireless signal processing unit for transmitting an intelligent monitoring ng a wireless signal to the target object and receiving a scattering wireless signal reflected from the target object; and a signal processing unit electrically coupled to the camera unit and the wireless signal processing unit for receiving a data corresponding to the image of the target object from the camera unit and a data corresponding to the scattering wireless signal reflected from the wireless signal processing unit. The signal processing unit analyzes the data corresponding to the image of the target object to obtain a status ate information and generates a reference signal according to the status information, and the reference signal is processed together with the data corresponding to the scattering wireless signal by the signal processing unit to generate a change detection signal.