Solid state cathodoluminescence is a brand-new excitation mode. In the device, electron acceleration layer plays a very important role in obtaining high energy hot electrons to excite organic luminescent materials in solid state cathodoluminescence. Two kinds of structural devices (A： ITO/MEH-PPV/SiO2/Al, B： ITO/MEH-PPV/ZnO/Al) were fabricated. The theoretical calculation and analysis show that the tunnel current and electric field was higher in SiO2 layer than that in ZnO layer under the same applied driving voltage. The experimental results show that the intensity of device A with SiO2 as electrons acceleration layer is stronger than that of device B with ZnO as electrons acceleration layer under the same driving voltage. And the result demonstrated that electrons in the conduction band of SiO2 can be heated to higher energy than that in ZnO.