Abstract: According to the damage and cracking of steel rail U78(produced in Luxemboury) in practical use,the authors sampled and tested ovens of different size,different steel rails of service route positions and steel rails of different parts.Macro and micro complete analysis of all the samples by eletron microanalysis,hardness measurement and metallographical microanalysis,etc,in order to give a full evalation of the quality and damage of all the tested steel rails.