Abstract: It was anatomic studied enlarging of stone cell group and the expanding of parenchyma cells during fruit development of Pyrus bretschneideri. The results indicate: Unequal thickness of fruit parenchyma cells'wall forms thick wall cell, thick wall cells develop to stone cell through cell wall re-thickness; The forming of stone cellmostly starts at 15 DPA and it commences largely within a week. The stone cells gather and emerge at 23 DPA and the diameter of stone cell group enlarges. The max diameter of stone cell group comes forth at 67 DPA. At the same time, the parenchyma cells grew and enlarged with two different methods, strip and ellip soid. The content of stone cell increases firstly, and then descends during pear fruit development. The max content of stone cell come forth at 51 DPA ( 18.95%). The content of stone cell is determined the forming of stone cell and the expansion of parenchyma cells during fruit development

Key words: pear, Pyrus bretschneideri, stone cell, parenchyma cell, natomic observe