As-received ZnSe crystal has been examined by cathodoluminescence spectroscopy ranging from 350nm to 850nm at room temperature for internal defects and inclusions. Two cathodoluminescence peaks of 462nm and 453nm were detected，of which the former was identified as intrinsic cathodoluminescence of ZnSe and the latter was caused by the crystal defect. The Zn:Se ratio of 6:4 was found by energy dispersive x-ray spectroscopy(EDS)，and the extrinsic cathodoluminescence peak of 453nm was attributed to additional Zn in excess of ZnSe stoichiometry.