An automatic paper separator comprises a belt conveying unit used for conveying paper materials, a paper separating platform located above the belt conveying unit, and a control frame used for supporting the paper separating platform and controlling displacement of the paper separating platform. A slot hole used for containing the paper materials is formed in the upper portion of the paper separating platform, and a sliding block is arranged at the lower end of the paper separating platform. The control frame comprises a transverse sliding shaft, supporting rods used for supporting the paper separating platform, a plurality of first supporting feet hinged to the belt conveying unit, and a plurality of second supporting feet fixedly connected with the belt conveying unit. The transverse sliding shaft is in sliding fit with the sliding block. The second supporting feet are provided with a lifting mechanism which is used for controlling the vertical displacement of one end of the paper separating platform.