A solid dust suppressant is prepared by mixing 40-90% of a water-soluble high molecular polymer, 5-40% of water-soluble high molecular glue, 0-25% of a moisture absorption humectant, 0.5-5% of a flexibilizer, 1-5% of an antiseptic and 3-10% of an osmotic agent, and has the characteristics of high film forming strength, low brightness and moderate viscosity. The viscosity (at 25DEG C), the pH value, the wind loss rate (under 30mm/s wind speed 5mins, %), the cured layer thickness, the film tensile strength, the film elongation at break and the material bursting strength of the solid dust suppressant are not lower than 8.0mPa.s, 6.0-7.0, not greater than 0.40, not lower than 11.25mm, greater than 11mpa, greater than 13% and greater than 0.05mpa respectively, and the solid dust suppressant realizes difficult brittle rupture after film formation, has a long effective dust suppression time and an ideal dust suppression effect.