Abstract: Aiming at the problem that when solid-liquid pump run,too much or little slurry would cause conveying system to work abnormally,the paper introduced design of a control system of solid-liquid pump based on PLC and introduced its software and hardware design in details.The system uses liquid level sensors to detect liquid level information of raw material groove and storage groove.PLC controls start and stop of solid-liquid pump according to the information and does photoelectric alarm.Simulation results showed correctness and validity of the system.Field application also verified its stability and reliability.