Abstract: Abstract: Calcium is an essential nutrient required for critical biological functions such as nerve conduction, muscle contraction, mitosis, blood coagulation, and structural support of the skeleton. Dietary calcium intake is of general interest for human beings, particularly for infants and young children, when growth is accelerated. Milk and milk products as effective calcium supplements are generally accepted by human race with their high bioavailability. However, less consumption of milk in industrialized countries leads to inadequate calcium intake. Therefore, it is important to explore an alternate source for calcium supplement. On the other hand, dried grape seeds are likewise rich in lipids (22.07%), carbohydrates (12.51%) and proteins (11.94%) (w/w) and grape seeds as by-product during juice production can be an alternative source of protein. Meanwhile, this study demonstrates that grape seeds are rich in calcium ((5.62±0.01) g/kg for embryonic cells and (6.32± 0.01) g/kg for intact grape seeds), which was identified by ICP-AES. The calcium was mainly distributed in the stroma of the amyloplasts and around the starch granules, which was observed under TEM (Transmission Electron Microscope). Further study indicates that water-soluble protein from grape (Vitis vinifera L.) seeds (WSPG) contained two major components, one of which was 11S globulin-like protein mainly responsible for the binding of calcium in WSPG and the other was a novel protein (Protein A). The calcium contents of protein isolate from each step were identified by ICP-AES as well. When a traditional alkali extraction and acid precipitation method was used for isolation of WSPG, many binding calcium ions were lost. It is worth noting that the protein composition of grape seed protein obtained by both 30%-50% (NH4)2SO4 sediment and the alkali extraction and acid precipitation method was nearly identical, which consisted of protein A and protein B at a ratio of 2 to 3, but the content of calcium in the grape seed protein by the ammonium sulfate sediment was approximately 3-fold larger than that by the traditional method, demonstrating that the ammonium sulfate sediment was a better way to isolate mineral-containing protein as compared to the traditional method. A high yield of calcium by the ammonium sulfate sediment could be derived from its mild condition, whereas acid and alkaline used in the alkali extraction and acid precipitation possibly inhibits the binding of calcium ions with grape seed protein. The following FT-IR (Fourier transform infrared spectroscopy) study showed that the prominent band of apo grape seed protein attributed to random coils turns (1 666 cm?1) was shifted to lower wave number (1 660 cm?1) with a marked decreased in intensity upon calcium binding with the protein and indicated that the binding of calcium to the protein stabilizes the secondary structure of WGSP by changing state of C=O. Moreover, the abundant amino acid residues were found in WGSP to be glutamic and aspartic acids, which accounted for about 26.7% and 9.0% of the total amino acid, respectively, and these amino acids might be beneficial for calcium binding. This study could provide a foundation for the preparation of mineral-containing protein in food industry. This method may have a potential use in food industry for isolation of mineral-containing protein from other sources.