Objective To investigate the rules and mechanism of neuroapoptosis during the development in mouse cerebellar cortex. Methods The neuroapoptosis of cerebellar cortex was visualized by the active Caspase-3 pAb immunohistochemistry and Hoechst 33258 staining from postnatal day 0 (P0) to adult mice. Westernblotting was used to study the expression of Caspase-3 and Caspase-8 in the cerebellum. Results Apoptotic cells density was the highest at P8，P5 and P9 in the external granular layer (EGL)，Purkinje cell layer (PCL) and internal gran BR>ular layer (IGL) respectively, and the density of apoptotic cells of each layer was lower in cerebellar cortex at P20. Activated Caspase-3 was expressed higher at P5, then decreased gradually until the disappearance at P14, at the same time activated Caspase-8 was expressed higher from P0 to P10, and then disappeared at P30. Conclusion It was an important period for neuroapoptosis in cerebellar cortex from P0 to P14, and cell apoptosis pathway that Caspase-3 was activated through cleaved Caspase-8 exists during the molding and growth in the mouse cerebellar