Abstract: Objective To investigate rule of protein expression and relation between protein expression and embryogenesis. Methods Seven kinds of embryonic organs including liver, spleen,kidney, stomach, skin, lung and thymus were taken from a 19 week-embryo by induced delivery.These tissues of different organs were embeded with paraffin, routine sections were performed. Then 21 kinds of antibodies were used to assay the components among the seven types of organs by immunohistochemistry. After this process, hematoxylin staining followed. Cell type, location and intensity of staining were observed and analyzed through microscope and its photos to find rule of protein distribution from the different embryonic organs and its relation with embryogenesis.Results There existed a significant differencs in statistics between the actual frequency and theoretical frequency of protein expression ( P ＜ 0.01 ). The differential cells from the same ancestor generally held the same groups of proteins. Conclusion Many proteins tend to distribute in groups in cells. This phenomenon has some relation with cell genesis, however, the cell isogenesis is not the only reason for protein distribution grouped.