With the development of electronics industry, especially the flourishing of electric vehicles and wearable flexible devices, dielectric polymers need to show high dielectric constant, low dielectric loss, excellent mechanical properties, and easy processability. However, the existing dielectric polymers cannot all meet these requirements. As a widely used dielectric polymer, PA11 has excellent mechanical properties, and its dielectric constant can be improved by adjusting chemical structure. Herein, we report a new copolyamide, PA Biuret-11 (COPAs), synthesized by copolymerizing biuret with high dipole density and PA11 with long aliphatic chains. In COPAs, biuret not only provides a lot of dipoles to increase the dielectric constant, but also limits aliphatic chains to flipping along with dipoles to decrease the dielectric loss. PA11 can provide the excellent mechanical properties and good processability. The results show that the dielectric constant of COPAs increases from 5.7 to 10.8 (at 20 ℃ and 10 Hz) and its dielectric properties are still stable at high temperatures (150 °C). Moreover, COPAs show a wide processing window from 164 ℃ to 385 ℃ and the introduction of biuret segments significantly enhances its elongation at break from 150 to 400% while maintaining its yield stress of 32 MPa, which mean better processability. Based on structural analysis and dielectric research, the high dielectric constant of COPAs is attributed to the weak hydrogen bonds which formed by twisted chains. This work represents a new strategy in dielectric polymers for achieving simultaneous high dielectric constant and excellent mechanical properties. [ABSTRACT FROM AUTHOR]