The force measuring device is designed to the study of the relationship between vibration amplitude, frequency, speed and traction resistance of the tractor If the design of the force measuring device which consists of a force measuring frame and three octagonal ring transducers is successful, the goal of real-time monitoring of the traction resistance in the process of vibrating sub soil may be reached. Also, the up, down, left and right margin of frame is designed to be adjustable, so that different kinds of tractor could link up with the force measuring device. With the vibrating sub-soiler machine, the vibrating resistance reduction experiments, which are mainly based on the change of the vibration amplitude, frequency and the speed of the tractor, may be done. The three levels of the vibration amplitude, frequency, and speed are as follows: vibration amplitude: 0.001 m, 0.002 m, and 0.003 m; frequency: 9 Hz, 10 Hz, and 12 Hz; speed: 0.1 m/s, 0.2 m/s, and 0.3 m/s. The experiment results showed that with the same speed and bigger vibration frequency, the tractor traction resistance is small and when the amplitude is 0.001 m, the vibration frequency is 10 Hz, and forward speed is 0.2 m/s, and the tractor traction resistance is the minimum.