Abstract: The rail temperarure rises when the linear eddy current hrake of high-speed train is working, which may lead to a change of rail physical characteristics or an effect on train operations. Therefore , a study concerning the characteristics of rail temperarure rise caused by eddy current has its practical necessity. In the research , the working principle of a linear eddy current brake is introduced and its FEA model is established. According to the generation mechanism of eddy current, the theoretical formula of the internal energy which is produced by the eddy current is deduced and the thennalload on the rail is obtained. ANSYS is used to simulate the rail temperarure changes under different conditions of thermal loads. The research result shows the main factors which contribute to the rising of rail temperarure are the train speed, brake gap and exciting current. The rail temperarure rises non-linearly with the increase of train speed. The rail temperarure rise curve is more sensitive to the exciting current than the air gap. Moreover, the difference stimulated by temperarure rising between rails of 60 kg/m and 75 kg/m is presented as well.