Aiming to reduce the impact of tractor jolts on the operating performance of the paddy field puddling and leveling machine, a passive vibration isolation system was added between them. The vibration data of the vibration isolation system were obtained through field experiments, and the effects of ground interaction on the system's performance were analyzed. To obtain the interaction relationship between the vibration isolation system and the ground, a vibration isolation system model for the interaction between the puddling and leveling machine and paddy field soil was established. To establish a complete model of the vibration isolation system, frequency domain integration of acceleration and the least squares method were used to identify the model parameters. In addition, the stiffness of the passive vibration isolation system was optimized based on the vibration isolation system model in contact with the soil. The results showed that due to ground interaction, the natural frequency of the vibration isolation system was increased by 8.5% , whereas the static deflection and the effective isolation frequency were reduced by 0.02 m and 6.4% , respectively. The identified parameters included an equivalent damping coefficient of 12 329 N·s/ m for the vibration isolation system, and equivalent stiffness and damping coefficients of 11 560 N/ m and 3 129 N·s/ m for the soil. The appropriate stiffness for the isolation system was determined to be 59 253 N/ m, which effectively isolated vibrations above 9 Hz. Under this condition, the RMS of the system’s displacement and acceleration responses were reduced by 29.1% and 58.4% , respectively.