Heat-treatment i s emphasized for its important role to qualify the heavy rail. The temperature and stress field of U71Mn heavy rail during the quenching process were simulated by the FEM software and various kinds of factors that may influence temperature and stress field distribut ion were investigated . The result shows that the main factors influenc ing the temperature and stress field distribut ion were the heating and holding time, as well as the pressure of air blast during the coo l ing, whose values would directly influence the final performance of the heavy rail after the heat treatment. It is significantly valuable for the choice of relevant parameters for the heat treatment of U71Mn heavy rail.