The invention discloses a dust removing device of a decorating machine. The dust removing device comprises a body, a support, a plurality of fixing portions, a printing and dyeing cloth input column, a waste cloth recovery column, a stretch column, a dust removing mechanism and a dust collecting mechanism, wherein the support is arranged on the body, the fixing portions are arranged on the support, the printing and dyeing cloth input column and the waste cloth recovery column are rotationally arranged on the fixing portions, the stretch column is rotationally arranged on the body, and the dust removing mechanism and the dust collecting mechanism are arranged on the body. Besides, the dust removing mechanism comprises a plurality of rotating plates, a plurality of dust removing columns and dust removing grains, wherein the rotating plates are rotationally arranged on the body, the dust removing columns are rotationally arranged on the rotating plates, and the dust removing grains are arranged on the dust removing columns. The dust collecting mechanism comprises a dust collecting box and a dust absorption barrel, wherein the dust collecting box is arranged on the body, the dust absorption barrel is arranged on the dust collecting box, and the dust collecting box and the dust absorption barrel are connected by the aid of a dust collecting tube. By the dust removing device of the decorating machine, the problem that embroidery cloth needs to be manually collected is solved.