Fatigue ratio of lamellar pearlite steel used for railroad rail is lower than the ratio of general steels. The reason is not clarified. It is reported the direction of lamellar microstructure in lamellar pearlite steel effects fatigue characteristics. In order to clarify microscopic deformation behavior of lamellar microstructure considered to effect fatigue characteristics, static tensile tests of lamellar pearlite steel was conducted, in this report. Using the plastic replica technique, microscopic deformation behavior, the initiation and propagation of micro crack was observed. By the observation, it is clarified that the crack initiates but does not propagate during static tensile test. The authors presume the fatigue of lamellar pearlite steel as follow: The grain size crack initiate at initial stage of fatigue process, and the crack act as initial defect of the lamellar pearlite steel. Based on the presumption, the fatigue limit of the lamellar pearlite steel was predicted, and the fatigue limit was confirmed by fatigue tests. As the result, the predicted fatigue ratio are 0.32~0.33 which show good agreement with the fatigue test result.