In this paper,the author introduces the characteristics of 300 t yacht handler,designs and analyzes the travelling and steering hydraulic system of the handler,and expounds the working principle of the travelling and steering hydraulic system.The differential force and differential adjustment of travelling,travelling braking and various steering modes such as straight,horizontal and in-situ rotation are analyzed and introduced.Yacht handlers are used to handle large ships,and their travelling and steering hydraulic system is an important part of the handler's hydraulic system,which plays a vital role in handling performance.The stability of the travelling system and the diversification of steering modes directly affect the maneuverability,handling stability and cost of the whole vehicle.