In order to solve the severe vibration problem of hilly orchard transporter in practice, a semi-active suspension system using CDC dampers was designed and the loading tests were carries out. An orchard road input model was first established as well. When using the road input model established to select a simulated road, the α is 0.9, the coefficient of corresponding road roughness is 4 096×10-6 m3, and the vehicle speed is 10 m/s. A road input model was created in MATLAB/Simulink, then the semi-active suspension and passive suspension models were established, and MATLAB was used to establish the Simulink model of the fuzzy PID controller based on the suspension system dynamics model. The parameters of the semi-active suspension were analyzed and adjusted to obtain the ideal simulation response results. The results showed that the performance of the semi-active suspension system is 10%-20% higher than that of the passive suspension system. Finally, the mechanical structure of the semi-active suspension system was designed and the loading test of the system was carried out. The mechanical structure of the semi-active suspension system is made up of elastic elements, shock absorber reformation, guiding mechanism and various parts connecting parts, and semi-active suspension. The system is arranged according to the layout space of the front axle. The shock absorbers are arranged in an oblique arrangement with a horizontal angle of 30°. The elastic elements are arranged vertically. The guide mechanism is installed in the middle of the front axle to limit the front and rear of the front axle and constrain the vertical movement trajectory. According to the fuzzy PID controller designed, the control circuit system is designed and the semi-active suspension is tested. The vibration test system is built using the vibration instrument and the vibration sensor and the vibration signal of the Z axis of the seat position of the vehicle is tested during driving. Under certain conditions of speed and load, the test results of the semi-active suspension before and after loading showed that the vibration reduction of the transporter equipped with the semi-active suspension reached 50%, meeting the design requirements of the semi-active suspension system. The vibration frequency range of the vehicle body equipped with a semi-active suspension system is greater than 8 Hz, indicating that the vehicle has good driving comfort. Although this paper has done a certain theoretical analysis on designing the semi-active suspension system of the wheeled transporter for hilly orchard, there are still many things that can be further studied and expanded. For example, neural network or genetic algorithm can be used to optimize the fuzzy PID controller so that it can respond better to road excitation. When the system is in motion simulation, Adams can be used to perform kinematics simulation analysis, analyze the mechanical performance of the system in motion, and optimize its design.