The invention relates to a powder feeder without a mechanical transmission mechanism, which can effectively solve the defaults caused by the malfunction, the clamping stagnation and the abrasion of a mechanical transmission mechanism of the prior powder feeder and accordingly ensures that the powder feeder has long service life, saves energy and stably feeds powder. The powder feeder adopts the technical scheme of comprising a shell and an air pipe, wherein a closed cavity which is through from top to bottom is formed in the shell; an air pressure chamber is arranged at the upper part of the closed cavity, and a powder storage chamber is arranged at the lower part of the air pressure chamber which is internally provided with an air inlet pipe and a powder air pipe; the upper ends of the air inlet pipe and the powder air pipe in the closed cavity are respectively provided with openings at the upper part of the air pressure chamber; the lower ends of the air inlet pipe and the powder air pipe penetrate through the shell towards the exterior of the shell; and the closed cavity, a powder-feeding cover with a sealing ring and a powder-discharging cover with a sealing ring form an integral sealing structure. The invention has novel and unique structure, low energy consumption, no mechanical abrasion, long service life, high working efficiency, small size and low manufacture cost.