Abstract: The standard hydraulic steering system of modern tractor is a load-sensing servo control system with a load-sensing signal channel, which is based on the hydraulic steering gear.On this basis, the double metering motor steering system and the flow amplification steering system are derived to achieve the purpose of reducing the driver’s control force and meet the requirements of large flow and fast steering.Based on the detailed hydraulic steering system schematic diagram and steering machine structure diagram, the composition and working principle of the hydraulic steering system are analyzed.