Abstract: Dielectric polymers with high energy density, high heat resistance, and low dielectric loss are ideal materials for next-generation power and electrical applications, such as high-temperature energy storage films for capacitors. Since high polarization and low dielectric loss are contradictory, high dielectric constant (ε_r) and low loss should be compromised. For intrinsic polymer dielectrics, the dielectric constant is attributed to electronic, atomic, and dipolar polarization. However, due to the characteristics of polymer molecular bonds, the dielectric constants of electronic and atomic polarization of hydrocarbon-based dielectrics are limited to below 5, and dipole polarization is effective to improve the intrinsic dielectric constants. This review focuses on the design strategy to achieve high energy storage density with high dielectric constants while reducing dielectric loss in intrinsic dipole glass polymers. The feasibility of freezing chain dynamics is analyzed from the perspective of main and side chains to prevent electron conduction and reduce dielectric loss. The mechanism of suppressing conduction current is revealed from the electronic structure perspective to achieve high energy storage density at high temperatures while maintaining high ε_r and high glass transition temperature (t_g). Finally, the challenges and critical points of developing polar polymers for film capacitors are summarized and discussed.