Abstract: Based on to the cracking phenomenon of U71Mn 60Kg/m trunk-line rail during its operation,macro-analysis and microscopic examination were adopted to analyze the cause for cracking at the end of the rail.Some new quenching techniques were discussed for the heat-treatment of the end of the rail using by high-speed circulating railway.The results show that the quenching techniques of surface of the rail was not suitable for the end of the U71Mn rail.The quenching layer is too thin to be used,and the thickness is not hom ogeneous,the hardness is too high or too low to meet the demand for mechanical property.The reasonable technique is to use the multi-muzzle profile modeling sprayer to heat,and the cooling and temper tech nology after heating must be controlled correctly,too.Better microstr ucture and performance will be gained if 50HZ induction heating technique be adopted.