To improve the construction efficiency,reduce labor cost and fuel consumption of the trailing suction hopper dredger,we carry out a research on the automatic control system for the discharge pipe operation.During dredging,the discharge pipeline is often blocked by slurry under the traditional semi-automatic dredging control system when it is operated by many people due to the complicated environmental condition and operation process.Four automatic controllers including the automatic dredging suction system (ADSS),automatic light mixture overboard (ALMO),automatic jet-pump controller (AJC) and automatic button mud-door controller （ABMC）are designed to realize the full-automatic control of the discharge pipe system,which can improve the slurry flow rate,reduce slurry concentration,and prevent slurry plugging.Meanwhile,the system can reduce the labor cost and fuel consumption,and improve greatly the dredging efficiency of the trailing suction hopper dredger.