A direct resistance heating simulation method is provided. In this method, a welding region and its peripheral region of steel sheets to be welded by a pair of electrodes are divided into a plurality of elements. A coupled analysis is performed such that a temperature, a metal structure, stress and strain at each element are determine in a mutually associated manner based on Joule loss obtained through a current analysis and a magnetic field analysis for each element. The coupled analysis is repeated to predict an effect of one or more parameters, including at least one of a frequency, a magnitude and an application time of electric current to be applied to the electrodes, a cooling time, a pressure applied from the electrodes to the steel sheets and a shape of the electrodes, on welding quality after a post-heating by direct resistance heating and to improve weld strength.