Abstract: Performance of cooling system is crucial to ensure stable operation of engine at a suitable temperature, and to improve its service life and fuel economy．Based on actual parameters of tractor engine, theoretical calculation of cooling system was carried out to determine heat dissipation, ventilation and water flow ; then parameters of each module of cooling system were selected to determine matching scheme of cooling system; performance of cooling system was verified．Test results showed that matching design of cooling system could meet cooling requirements of engine, and could provide a reference for matching design of the same type of cooling system．