The microstructures of lithiated graphite were studied using high-resolution transmission electron microscopy (HRTEM) and x-ray diffraction (XRD). HRTEM shows lattice images of the (001) layers of LiC6 with layer spacing of 3.70 Angstrom, consistent with XRD. The morphology and distribution of the LiC6 and LiC12 phases were investigated by dark field image and selected-area electron diffraction in TEM. The results indicate that LiC6 and LiC12 phases can coexist in the lithiated graphite particle.