The invention relates to a powder taking device for coal mine tunnel geological determination. The powder taking device comprises a coal mine drilling machine, a drill rod (10), a collecting box (20)and a metering device, wherein the coal mine drilling machine outwards extends to support a drilling machine (93); the drill rod (10) is arranged on the drilling machine (93) and is used for taking powder through hole drilling; the collecting box (20) is arranged on the drill rod (10) and is used for collecting coal powder formed through hole drilling; and the metering device is connected with thecollecting box (20) and is used for weighing the coal powder formed through hole drilling. Through the coal mine drilling machine and the drill rod (10), the hole drilling in each geological positionof a coal mine tunnel is realized; through the drill rod (10) and the collecting box (20), the collection concentration of the coal powder is realized; through the metering device, the online weightmetering of the coal powder is realized; the coal mine drilling machine and a driving chassis are not a whole, so that the power taking operation on each geological position of the coal mine tunnel isrealized; and the accurate monitoring on the geological condition of the coal mine tunnel is improved.