The invention discloses a large-space descaling device and a descaling method with an evenly distributed aeroacoustic composite field. The descaling device includes a device inlet, an aeroacoustic field-distributed space, an acoustic soot blowing device, a descaling space, and a device outlet. Among them, there is an aero-acoustic field arrangement space behind the device entrance, a sonic soot blowing device is installed in the aero-acoustic field arrangement space, a descaling space is set after the aero-acoustic field arrangement space, and a device outlet is set after the aero-acoustic field arrangement space; An aeroacoustic deflector is arranged behind the sonic soot blowing device in the space, and the sounding direction of the sonic soot blowing device faces the aeroacoustic deflector. The descaling method is that after the airflow enters the device, the airflow is firstly averaged to form the airflow after the average flow, and then it is fluidized together with the sound waves emitted by the sonic soot blowing device in the aeroacoustic average field layout space, and then the airflow is averaged by the aeroacoustic deflector. After flow and rectification, it enters the descaling space to descale the equipment set in the descaling space, and at the same time, it can effectively prevent local serious scaling.