Abstract: According to the problems of high starting current,instability of power supply and complex wiring in control system of LWZ1400×2000A horizontal solid bowl centrifuge,based on the experiment and research in working site,the controlling mode was transformed from relay+contactor into touch screen +PLC controlling the soft starter.The practice indicated that the second controlling mode has stability of starting current and stability of power supply,which ensured that horizontal solid bowl centrifuge stable operated.