Abstract: The skin lesion of a patient with pemphigus vulgaris was observed under EM.We found the acantholysis occuried on the top of basal layer where the connection between squamous cells became. looser,the intercellular space between desmosomes became wider, and the tonofilaments disappeared.The surface of squamous cells was smootli, but the shape of nuclei was irregular and the nuclei were surrounded with light-stained halos. Mitochondria showed vacuolar degeneration.