Abstract: The structure of aleurone cells and storage reserves in the ungerminated mature jobstears (Coix lacryma-jobi L. ) caryopsis were observed with both light microscopy and electron microscopy. The cell of aleurone layer has a nucleus, numerous lipid bodies, aleurone grains, starch grains, and ER fragments. The lipid body is enclosed by an electron-dense line. The aleurone grain with a globular inclusion is composed of protein, polysaccharide, and niacytin. The globular inclusion contains lipid and phosphate. The protein bodies in the starchy endosperm reveal concentric rings in ultrastructure.