Abstract: In order to solve problems such as the aging of LJ-2 centrifuge’electric drive system and its high failure rate, PLC and DCS800 digital DC variable speed devices are adopted to upgrade the electric drive system. Industrial control computer or HMI are uesd as an upper-level supervision unit. The machine auxiliary transmission is updated. Furthermore, instruments on arm of the centrifuge can communicate with computers on the ground through optical fiber. The centrfuge has the ability to transfer high pressure oil from the ground hydraulic power supply to the devices on the arm of the centrifuge. As a result, the electric drive system enjoys better performances and higher reliability.