Abstract: In the experiment, HRB335 steel was treated by impulse current, and the maximum current, frequency and processing time were considered together. The optimal result is the following: the current density is 0.021~0.025 A/mm², the frequency is 1 Hz and the processing time is 30 s or so. The maximum equiaxial crystal ratio is up to 95% and the crystals are obviously refined. Compared with the others' discoveries the primary inclusion was made that electropulse effect may be independent of steel species. Different opinions about the columnar crystal broken theory were proposed. It is considered that liquid level fluctuation phenomena are for too much oxygen is dissolved into the metal.