The crystal structure of medicated realgar in China was validated as α-As4S4 by X-ray diffraction and Raman spectroscopy in the present paper. Ten batches of medicinal realgar were analyzed including realgar ore, medicinal realgar powder, and prepared Chinese medicine. Identification of two As4S4 polymorphs confirmed that the crystal structure of medicated realgar in China is α-As4S4. Studies on 18 batches of preparative realgar powder showed that processing of realgar can not change the crystal structure of realgar.