The invention discloses a dust inhibitor, which comprises the following raw material in percentage by weight: 0.6 to 0.8 percent of plant seed colloid, 0.1 to 0.3 percent of modified cellulose, 0.05 to 0.09 percent of dispersant and the balance of water. The dust inhibitor can be prepared at normal temperature in a common mixing equipment from mixed aqueous solution of plant seed colloid, modified cellulose, crosslinking agent, dispersant and reinforcing agent; and after being prepared, the dust inhibitor can be sprayed onto the surface of coal in carriages to allow the coal to form a layer of cured film on the surface, the viscosity of the film is high, the wind corrosion rate of the film is low, so that the dust pollution along railways in railway transportation of the coal and the dust loss of the coal are avoided. Besides, dust inhibition in railway coal transportation, the dust inhibitor can be used for dust inhibition on roads in mining areas, urban roads, constructions sites, stations, ports and the like so that the dust inhibitor can be used almost without being limited by fields, and the dust inhibitor can be widely used.