The blast drying of lump ore in belt press is taken as the research object. With the help of Fluent software, a coupled mathematical model of mass, momentum, energy double-equation and water migration equations in the bed of porous media is established, and the variation law of the dehumidification amount of the trolley under different process conditions is studied. The results show that: with the increase of the blast temperature, the moisture removal amount of the material layer increases, and the water vapor condensation occurs at the leading edge of the material layer around 150 s; under the conditions of the blast speed of 1. 43 m/s and the blast temperature of 300 ℃, the moisture removal amount of the material layer has little relationship with the initial moisture content; with the increase of the blast speed, the moisture removal amount of the material layer increases, and at 360 s, 1.08, 1.43, 1.79 m/s, the maximum moisture removal from the material layer is 31%, 36% and 40%, respectively, and the larger the speed, the less the condensation zone, but the higher the condensation value.