The invention discloses a dual-screening device for materials. The dual-screening device comprises a left support and a right support. A left rotary shaft is rotationally connected to the upper portion of the left support. A right rotary shaft is rotationally connected to the upper portion of the right support. The right rotary shaft is located on the upper right of the left rotary shaft. A left transmission wheel is fixedly connected to the outer side of the left rotary shaft. A right transmission wheel is fixedly connected to the outer side of the right rotary shaft. A conveying belt is sleeved between the left transmission wheel and the right transmission wheel. The outer side of the conveying belt is provided with a plurality of first-level screening holes. A plurality of transmissionlugs are fixedly connected to the inner side of the conveying belt. A fixed plate is fixedly connected between the left support and the right support. An inclined screening plate is slidably connectedto the middle of the fixed plate. The upper portion of the inclined screening plate is provided with a plurality of second-level screening holes. Compared with the prior art, the dual-screening device has the beneficial effects that structure is simple, use is convenient, the materials are divided into three kinds of different-size materials through two levels of screening during use, then pricescan be made according to sizes, and higher benefits are obtained.