The working characteristics of diesel engine and variable frequency motor are different,which causes the difference of pump characteristic curve.We analyze the equipment characteristics of diesel engine and variable frequency motor,study the influence of variable frequency motor drive,single speed ratio gearbox and multi speed ratio gearbox drive of diesel engine,limited power drive of diesel engine on the performance of mud pump,and compare and analyze the transmission efficiency,speed range,economy and adaptability of each transmission condition for reference in dredging engineering field.The results show that the transmission efficiency of the diesel engine drive is higher than that of the variable frequency motor drive.The speed range of the variable frequency motor drive is wider than that of the diesel engine drive.The diesel engine can provide more power under the condition of medium discharge distance.The complexity,initial investment,energy utilization and safety of the variable frequency motor drive system are higher.