The invention discloses a masking paper separating device. The masking paper separating device comprises a connecting seat, wherein cylindrical barrel with an opening in one end is fixedly arranged on the connecting seat; a part, which is positioned in the cylindrical barrel, of the connecting seat is rotatably connected with a guide shaft; a driving motor which is used for driving the guide shaft to rotate is fixedly arranged on the connecting seat; air tap assemblies which are used for blowing air to the guide shaft are arranged on the side wall of the cylindrical barrel; a sucking pen assembly which is used for sucking masking paper is arranged above the guide shaft; the masking paper is stacked on the guide shaft positioned in the cylindrical barrel; the driving motor drives the guide shaft to rotate; the masking paper correspondingly rotates along with the guide shaft to generate a centrifugal force; the air tap assemblies blow the masking paper so that the masking paper stacked on the upper part of the guide shaft is separated from one another; when the masking paper positioned on the top layer is thrown to the upper end of the guide shaft, the sucking pen assembly sucks the masking paper, and the sucked masking paper moves to a set position through a corresponding moving mechanism, so that separation of the masking paper is realized effectively. The masking paper separating device has the characteristics of simple structure, practicality and high efficiency.