The invention relates to a rotation driving mechanism of a small-piece cleaning machine. The rotation driving mechanism is characterized in that the rotation driving mechanism comprises a rotating motor reducing gear, a rotating basket transmission shaft, a transmission bearing pedestal, a transmission bearing pedestal fixing plate and a driving chain wheel; the rotating motor reducing gear is supported and fixed through a motor supporting frame assembly, and an output shaft of the rotating motor reducing gear is connected with the upper end of the rotating basket transmission shaft through a coupling in a downward mode; the rotating basket transmission shaft is installed inside the transmission bearing pedestal under the supporting effect of a transmission shaft supporting assembly; the transmission bearing pedestal is fixed onto a transmission bearing pedestal fixing plate through a bolt; and the lower end of the rotating basket transmission shaft is provided with the driving chain wheel. The rotation driving mechanism of the small-piece cleaning machine is ingenious in structure, reasonable in design, stable and reliable to operate and capable of efficiently driving a rotating basket assembly to rotate and guaranteeing the cleaning effect. Moreover, the manufacturing cost and using cost are made lower.