Abstract: A back drilling processing method for a circuit board includes: obtaining a board to be back drilled, wherein the board includes a target signal layer and at least two conductive reference layers; drilling a through hole at a set position of the board, and obtaining an actually measured spacing between two conductive reference layers; in response to a hole to be back drilled being of a first type, determining a target back drilling depth; controlling a drilling bit to drill for the target back drilling depth towards the target signal layer; in response to the hole to be back drilled being of a second type, determining a target relative height of a back drilling end point relative to a machine; and controlling the drilling bit to drill for the target relative height towards the target signal layer. The back drilling does not drill through the target signal layer.