In the present work, we crystallographically examined intergranular cracks initiated on Alloy 600 in a simulated PWR environment by using EBSD. The cracks initiated on a flat tensile specimen of the alloy in a short period of slow strain rate tests (SSRTs), that is, the initiation of cracks was accelerated due to the asperity of the specimen surface induced by mechano-chemical polishing with colloidal silica suspension prior to the SSRTs. As thick oxide films were formed on the specimen surface during the SSRTs, the sputtering of the films was carried out for the removal of the film. After the sputtering, clear crystallographic information such as inverse pole figures (IPFs) on the specimen surface could be obtained. Based on the information, the intergranular cracks were crystallographically analyzed. Furthermore, three-dimensional characterization of the cracks was also performed.