The invention discloses a mechanical arm device for powder material reservoir cleaning. The mechanical arm device for the powder material reservoir cleaning comprises a fixing base, a central column which is perpendicular to the fixing base is arranged in the center of the top of the fixing base, a lifting hook is fixed at the top end of the central column, a plurality of telescopic supporting arms which are uniformly distributed along the peripheral direction of the central column are arranged at the top surface of the fixing base, the outer ends of the telescopic supporting arms are fixedlyconnected with a supporting base, a first air cylinder is installed between the telescopic supporting arms and the central column, a rotating mechanism is installed at the bottom of the fixing base, the two ends of a first rotating arm are hinged to a rotating mechanism and a second rotating arm correspondingly, one ends of the telescopic arms are inserted into the other end of the second rotatingarm, and the other ends of the telescopic arms are fixedly connected with a tail end executing mechanism; and a second air cylinder is hinged between the rotating mechanism and the first rotating arm, a third air cylinder is hinged between the first rotating arm and the second rotating arm, and a fourth air cylinder is fixedly connected between the second rotating arm and the tail end executing mechanism. The mechanical arm device is complete in function, convenient to operate and high in environmental adaptability, the cleaning speed of a reservoir can be increased, and the working environment of workers can be improved.