Abstract: Aiming at problems of high density planting of flax and inconvenient operation of large machinery，driverless self-propelled dry land flax spraying truck was designed.Brushless DC motor and electric push rod were used as steering control components，and STM32 single chip microcomputer was used as control core of flax spraying truck.Spraying truck adopted two-way traffic between 2.4 GHz radio remote control device and single chip microcomputer to control walking speed，turning radius and spraying mode.Program was wrote by Keil uVision5 software to make decision and control for each action process of spraying truck.Simulation results showed that maximum left turning angle was 35.9°，maximum right turning angle was 25.7°，practical use steering angle was±25°，minimum turning radius was 4 m.Steering system met design requirements and it provided technical support for intelligent obstacle avoidance and intelligent operation of flax spraying truck.