The invention discloses a powder spraying device and a powder spraying method for an efficient vanadium extracting process of a converter, belongs to the technical field of metallurgy, and aims to solve the technical problems of poor dynamical condition, low oxidation conversion rate of vanadium and the like in the vanadium extracting process of the converter. The device comprises a powder spraying tank system, a PLC (programmable logic controller) control system, a gas adjusting valve set and a powder spraying gun. The powder spraying rate is accurately and continuously controlled by adjusting the frequency of a rotary feeding tray motor, the powder spraying gun has a double-sleeve structure, carrier gas powder spraying is adopted in a central pipe, meanwhile, auxiliary blowing gas ensures continuous operation of the powder spraying process, and circular seam blowing protective gas protects the powder spraying gun. The powder spraying gun is arranged on the side or the bottom of the vanadium extracting converter, and protective sleeve bricks are embedded around the powder spraying gun. The device is suitable for the vanadium extracting converter of 10 to 200 tons, can spray 50 to200kg/min iron concentrate powder in the vanadium extracting process of the converter, improve the dynamical and thermodynamic conditions of vanadium extraction of the converter, reduce the content of half steel vanadium to be less than 0.03 percent and improve the content of vanadium slag (V2O5) by 2 to 5 percent, meanwhile, is favorable for shortening the vanadium extracting smelting period of the converter, and realizes efficient vanadium extraction of the converter.