Crack can constantly expand and then cause invalidation, even cause catastrophic damage under the reciprocating loading. Based on remanufacturing, high energy pulse current impacting device was used to treat 316 austenitic stainless steel containing prefabricated unilateral fatigue crack. The influence of high density pulse electric current on the microstructure at crack tip was investigated by means of metallographic microscope, X-ray diffraction, electron backscattered diffraction (EBSD) and transmission electron microscope (TEM). And the evolution of microstructure by melting treatment was analysized. Results show that the sturture at crack tip obviously became refinement after the pulse current processing, and the gradient structure including the columnar crystal area, recrystallization zone and matrix was observed. Due to the rapid heating and cooling, the generation of high-speed electronic wind, electrically induced plasticity effect, the thermodynamic barrier of recrystallization or phase change was reduced by pulsed current treatment. The rate of nucleation was increased, inhibiting the grain growth process. Therefore the grain size of recrystallization zone was smaller than that of the matix, and hence the mechanical properties of materials was improved.