The intotfacial sDace charge distribution between ZnO varistor ceramics mad different collar coating matedals was investigated using the Pulsed Electroacoustic Method (PEA) and Thornlal Stimulated Current (TSC) methods. The experimental results show that a large amount of sDace charge accumulates at the interface between ZnO varistor ceramics and polyester polyurethane. while there is less spacc charge presents attheinterface betwean ZnO varistor ceramics and polyester modified silicone. The PEA results show that the inlroduction ofinorganic glass between ZnO varistor ceramics and organic coating materials can greatly reduce the amoullt of space charge. The results from the surface flashover measurement,which was based on 4/10 Bs stcep irepulse current, indicated that more space charge present attheinterface between ZnO varistor ceramics and coating matarials will lead to lower withstanding flashover capability of ZnO bloeks sincc the electric field can be deviated due to the existence of interracial space charge．