Objective To observe the expression of LAPTM4β in mouse oocytes and preimplantation embryos， and to understand the effect of LAPTM4β in the development process of embryos， which would thus contributes to the study of gene regulation in the developmental process of embryos. Methods Totally 50 oocytes and early embryos were collected from the uteruses or uterine tubes of 50 mice. The expression and intracellular localization of LAPTM4β in mouse oocytes and preimplantation embryos were studied by confocal laser scanning microscopy（CLSM）technique and immunohistochemical staining method, using the Maticam2206 image analysis system as a semiquantitative method. Results 1. CLSM technique: In the oocytes and pronuclear stage zygotes, LAPTM4β distributes nonuniformly and had a stranger expression near the membrane. In the embryos of 2 cells，4 cells or 8 cells stage and the morula stage， the expression of LAPTM4β in blastomeres cytoplasm was contagious distribution, and it was also stronger near the membrane and the polar body. There were LAPTM4β positive expressions in the trophoblast cells and inner cell mass of blastocysts. 2.Immunohistochemistry：Dilute brown granules have been seen in the oocytes. There were deep brown granules in the embryos of 2cells，4cells，8cells stage and the morula, and brown granules in the trophoblast cells and inner cell mass of blastocysts. 3. Iimage analysis system: The expression of LA