The invention provides a thin spray sealing material, which contains 15-55% of RD type polymer powder, 30-60% of inorganic filler, 14.5-40% of inorganic film-forming agent, and 0.5-5% of other auxiliary agents by weight percentage. %. The thin spray sealing material of the invention adopts RD type polymer powder as the main film-forming component, and can be sprayed to form a film by adding water, without by-products, VOCs and reaction heat, convenient and inexpensive to install, transport, store and use; Film-forming, ductility, permeability, environmental protection, flame retardancy, and can achieve sufficient strength, can replace shotcrete support in bolt-and-shot support technology. The invention also provides an open-type powder injection equipment with simple structure, low noise and no dust emission, which is suitable for the use of the thin-spraying sealing material of the invention, which includes a venturi gas-material mixing pipe, a blanking pipe, and a compressed air source. , the spray gun is communicated with the outlet of the venturi gas-material mixing pipe through the conveying pipe, and the spray gun is also provided with a spray nozzle which is communicated with the spray gun and is used for spraying atomized water into the spray gun.