See the supplementary material for more details of sample preparation and STM measurements, temperature dependent topography of CrCl3-Graphene (Figure. S1), RHEED and structure model of CrCl3-Graphene (Figure. S2), growth of CrCl3 on different substrates (Figure. S3), more STM images and I-V curve of Type I GBs (Fig. S4), Bias-dependent image and I-V curve of Type II GBs (Figure. S5), STM image of CrCl3-HOPG (Figure. S6), and line profile along two types of GBs under negative bias voltage (Figure. S7).