The invention discloses a dust removal device of a sanding machine. The dust removal device comprises a box body, wherein two sides of the bottom of the inner wall of the box body are fixedly connected with support plates; the back surface of the top of each support plate is movably connected with a rolling shaft; the bottom of the inner wall of the box body is fixedly connected with a support rod; the top of the support rod is fixedly connected with a fixed plate; the top of the fixed plate is fixedly connected with a cushion block; the top of the cushion block is fixedly connected with a first motor; an output end of the first motor is fixedly connected with a sanding rotating shaft; and cloth is arranged at the bottom of the sanding rotating shaft. Through coordinated application of the box body, a slide bar, a slip ring, a sucker, a suction head, a motion bar, a second motor, a turntable, a movable plate, a telescopic hose, a blast blower, a dust box and a discharge pipe, the effect of collecting willow catkins is achieved and the problems that the production efficiency of the cloth is reduced and the production cost of the cloth is increased due to the fact that the willow catkins cannot be collected by the dust removal device of the sanding machine are solved.