Abstract: In order to reduce the field turning radius and field turning rolling area of ratooning rice harvester, combined with the agronomic requirements of ratooning rice harvester in the first season, a rear axle steering system of triangular crawler ratooning rice harvester is designed, the structure of the rear axle steering system is designed, the virtual prototype simulation analysis is carried out by RecurDyn, and the modal analysis of the rear axle is carried out by ANSYS, The lowest natural frequency of the rear axle is132.28hz, which avoids the working excitation and will not resonate during operation. Finally, a field experiment was carried out to verify the reliability of the simulation results, which can provide a reference for the turning theory research of later ratoon rice harvester.