The saturation behavior in exciting power Pexcite is the specific characteristic in low voltage cathodoluminescence due to the high resistivity of the phosphor, causing the saturation behavior in field emission display. With the increasing of current density j, the saturation behavior in Pexcite directly results in the saturation of electron-hole (e-h) generation rate gnum. The e-h generation region X would shrink, resulting in the drastic increase of e-h concentration generation rate gcon, causing the decrease in probability ηet of an e-h pair exciting an activator. In addition, the radiative transition probability ηrad of an excited activator would be decreased due to the shrinkage of X and increase of temperature. To restrain the saturation behavior in low voltage cathodoluminescence, the ultimate method is to lower the resistivity of the phosphor. By introducing In2O3 conductive component into Y2O3:Eu3+ phosphor, restrained saturation beha- ior in cathodoluminescence of Y2O3:Eu3+ phosphor was effectively achieved.