Abstract: The U71Mn rail,whose type was 60 kg/m,had been laid in the joint of main line and the station port for more than 50 days and peeled on the rail tread. The reason was analyzed by means of chemical composition analysis,macrostructure and microstructure examination etc. The results showed that,when the train ran rapidly,suddenly the contingency happened,the driver adopted the emergency brake scheme to avoiding danger,then the powerful brake force had caused the wheel and the rail to contact abruptly and closely,at the same time,the large friction was generated to cause the crack,and the phase change to generate the martersite was happened in rail tread by high temperature. The crack and martersite had been rolled repeatedly by wheel,finally,the peeling happened on the rail tread.