Epoxy molding compound, with excellent electrical insulation and mechanical properties as well as low water absorption, has been widely used in insulation application of generators, motors, transformers, LED drivers and other electrical apparatus. With the power increase of the semiconductor device, the rigid requirement of electrical behavior of packaging materials becomes necessary. Here, the electrical performance of epoxy molding compound have been investigated from aspect of volume resistance. Types of epoxy resin, harder, and ion catchers on the influence of electrical performance of epoxy molding compound were carried out. And the results disclosed that epoxy molding compound with epoxy resin D and phenol hardener H possess the highest volume resistance, epoxy molding compound combined with epoxy resin C and phenol hardener G showed the lowest data, Higher Tg contribute to higher volume resistance. Ion catchers showed positive effect on the volume resistance of epoxy molding compound with small amount, and there is a download trend of EMC volume resistance with the ion catcher content increasing from 1% to 2%. And ion catcher C made greater contribution to the volume resistance of epoxy molding compound compared to ion catcher A and ion catcher B when adding at the same level.