Abstract: Influence of calcium on development and cell ultrastructure of 'Fuji' fruit was researched. Within 30 days after full blossom, EGTA and CaCl2 were applied in three times. The results showed that the treatment of CaCl2 made the electron dense bigger in cell wall and plastid; while EGTA effected the cell shape, and result of cell distort, especially within 20 days of full blossom, after 10 days of full blossom, starch grain was observed. CaCl2 inhabited the development of fruit, and EGTA enhanced the development of transeverse direction of fruit, apart from the treatment of 30-days after full blossom.