Abstract: The high cycle fatigue property of two kinds of EA4T axle steel with different components was studied.The microstructure of the steel was analyzed by optical microscopy.The results show that the increase of alloying element content effectively improved the hardenability of the steel,which led to the decrease of the size and quantity of proeutectoid ferrite and the grain refinement.The low content of sulfur reduced the number of inclusions.These factors together effectively improved the fatigue strength of the steel.