【Objective】 The objective of this research was to clarify structural characteristics of aleurone cells, sub-aleurone cells and central starchy endosperm cells. 【Method】 We observed and investigated rice endosperm using a light microscopy, a transmission electron microscopy and a scanning electron microscopy. 【Result】 During the differentiation process of aleurone cells, the large vacuoles were transformed into protein storage vacuoles of small volume and protein storage vacuoles were transformed into aleurone granules. There were more layers of aleurone cells in the dorsal part than in the ventral part of caryopses. However, the formation and accumulation rate of aleurone granules was slower in aleurone cells of the dorsal part of caryopses. Sub-aleurone cells initially included some lipid bodies, and later lipid bodies disappeared and amyloplasts and protein bodies in them increased gradually. Central starchy endosperm cells included amyloplasts and protein bodies. Vacuolar protein bodies occupied the major part of total protein bodies and they could fused with one another to be larger. Starch accumulation rate of central starchy endosperm cells was evidently quicker than that of sub-aleurone cells. In mature caryopses, amyloplasts were very dense in central starchy endosperm cells, amyloplasts were sparser in sub-aleurone cells of dorsal and lateral parts of caryopses and amyloplasts were sparsest in sub-aleurone cells of the ventral part of caryopses. 【Conclusion】 Structural differences of aleurone cells and sub-aleurone cells in dorsal and ventral parts of rice caryopses might be related to nutrient absorption and translocation. Developmental rate of amyloplasts in central starchy endosperm cells was quicker than that in sub-aleurone cells.