The invention provides an air powder selecting device. The air powder selecting device comprises an air box, a vertical material channel is arranged in the air box, a feeding opening is formed in theupper end of the material channel, a discharging opening is formed in the lower end of the material channel, a turbulent flow cavity is formed in the position, located on the left side of the materialchannel, in the air box, an induced air channel is formed in the position, on the right side of the material channel, of the air box, a fine powder outlet is formed in the inner end of the induced air channel, and faces the turbulent flow cavity, a blind window is arranged on the fine powder outlet, blades of the blind window are inclined downwards and faces the material channel, a fine powder outer outlet is formed in the outer end of the induced air channel, an air blowing channel is arranged at the position, located below the fine powder outlet, in the air box, an air blowing outer inlet is formed in the outer end of the air blowing channel, an air blowing inlet is formed in the inner end of the air blowing channel, and faces the turbulent flow cavity, and the air blowing inlet is close to the fine powder outlet. Large-particle materials doped in fine powder fall in a discharging opening under the effect of inertia separation and collision separation, and the device is small in whole size, simple and compact in structure and good in fine powder removal effect.