The utility model discloses a filtering device for a soldering flux. Box body, the top of the right side of the box body is fixedly connected with a rotating box; the bottom of the inner wall of the rotating box is fixedly connected with a first motor; an output shaft of the first motor is fixedly connected with a threaded rod; the left side of the threaded rod sequentially penetrates through therotating box and the box body and extends into the box body; the end, extending into the box body, of the threaded rod is rotationally connected with the left side of the inner wall of the box body; and the surface of the threaded rod is in threaded connection with a threaded sleeve, the top of the threaded sleeve is fixedly connected with a sliding rod, the top of the sliding rod is in sliding connection with the top of the inner wall of the box body, and the bottom of the threaded sleeve is fixedly connected with a fixing frame. According to the filtering device for the soldering flux, the loss of the soldering flux during filtering is reduced, the cost is saved, the grinding effect is improved to the maximum extent, the filtering speed is increased, the working efficiency is improved, and the working quality is improved.