With the development of semiconductor power devices, packaging materials with excellent heat resistance and insulation properties are increasingly required. In this work, the heat resistance and electrical properties of epoxy resins (EP) are improved by introducing bismaleimide (BMI) with both imide ring and benzene ring structures. The results show that the introduction of BMI can increase the glass transition temperature (T-g) of the EP. The electrical conductivity and DC breakdown of BMI/EP are systematically investigated, and the results show that the electrical conductivity decreased and the DC breakdown field strength increased. The dielectric-temperature spectrum demonstrates that both the dielectric constant and dielectric loss decreased from room temperature to 150 & DEG;C. In summary, the introduction of BMI improves the heat resistance and insulation properties of the BMI/EP, which shows good potential for use as high-temperature electronic packaging material.