The invention provides a device of feeding solid powder into a high-speed air flow. The device mainly comprises a supersonic spray pipe, a lateral annular pore plate gas inlet barrel, an auxiliary feeding nozzle, a charging cabin, a feeding pipe and the like. Gas enters through the lateral annular pore plate gas inlet barrel and carries materials fed from the charging cabin and the feeding pipe to collide with a target if being accelerated by the supersonic spray pipe, and the auxiliary feeding nozzle can feed in an auxiliary manner, so that the problem that a powdery material which is fed is likely to block is solved.