Airflow type gravel screening device

The invention relates to the technical field of airflow screening, and discloses an airflow type sand and stone screening device which comprises a screening box body, a first screening mechanism and a second screening mechanism which are arranged up and down are arranged in the screening box body, and the first screening mechanism comprises a screening net plate; the second screening mechanism comprises a rectangular mounting frame and a combined screening net arranged in the rectangular mounting frame, the rectangular mounting frame is obliquely arranged, the diameter of screening holes of the combined screening net is gradually increased from the high end to the bottom end of the rectangular mounting frame, and an airflow pipe is mounted on the side wall, close to the high end of the rectangular mounting frame, of the screening box. A plurality of airflow holes are obliquely formed in the side wall, close to the rectangular mounting frame, of the airflow pipe; the airflow pipe blows out strong airflow, so t