Abstract: Zeolite imidazolate framework particles were embedded into polypyrrole tubes (mass of 30,60,120 mg) by in-situ growth method, and then carbon-based composites were prepared by carbonization and activation with one-step heat treatment. The microstructure and electrochemical properties of the materials and the electrochemical performance of the assembled double-layer supercapacitor were studied. The results show that the composites were composed of carbon nanotubes and nitrogen-doped carbon particles on the outer surface of the tubes; the composites had large specific surface area and high nitrogen content, and the micropore diameter was concentrated at about 1 nm. The composites had good charge-discharge reversibility and rate performance, and exhibited typical double-layer capacitance behavior. The electrochemical performance of the composites with 60 mg polypyrrole tubes was the best under the same condition, and the composite had the largest specific capacitance of 283 F·g^-1 at current density of 1 A·g^-1. The symmetrical supercapacitor assembled by the composite had excellent cycle stability with specific capacitance retention rate of 91.5% after 3 000 cycles at charge-discharge current density of 2 A·g^-1 and with energy density of 9.15 Wh·kg^-1.