The invention discloses a single-motor drive system used for a grinding mechanism of a silicon wafer dual-face grinding machine. The system comprises a motor, a grinding driving mechanism, a first-stage transmission mechanism and a second-stage transmission mechanism; a main driving gear is arranged on a motor driving shaft of the motor, the grinding driving mechanism comprises a driving gear of aloose star wheel piece outer ring driving wheel, a lower grinding disc driving gear, a driving gear of a loose star wheel piece inner ring driving wheel, an upper grinding disc driving gear and the like, the first-stage transmission mechanism is in transmission connection with the main driving gear and drives the driving gear of the loose star wheel piece inner ring driving wheel and the upper grinding disc driving gear to simultaneously rotate, and the second-stage transmission mechanism is in transmission connection with the first-stage transmission mechanism and drives the driving gear ofthe loose star wheel piece outer ring driving wheel and the lower grinding disc driving gear to rotate simultaneously. According to the single-motor drive system used for the grinding mechanism of thesilicon wafer dual-face grinding machine, the making benefits of the grinding machine can be improved, guidance of a silicon wafer grinding process is simplified, operation efficiency of the grindingmachine is improved, and the mis-operation risks are reduced.