Display omitted •This was the first application of oxygenated vacancy cobalt tetroxide/polypyrrole(Ov-Co3O4@PPy) composites in the field of supercapacitors;•Regulate the concentration of NaBH4 solution (essentially the amount of Co2+), realize the enhancement of the specific capacitance of the material and the diversification of the morphology, and the trend of the obtained concentration and specific capacitance can be widely used in the field of defective transition metal oxides;•A new idea for constructing a defective transition metal oxide/conductive polymer core–shell structure was proposed, in which the vacancy structure and the core–shell structure together impart high specific capacitance and high energy density to the material. Effective controllable manufacturing oxygen vacancy and polypyrrole coating can optimize the capacitive and cyclic properties of Co3O4. Herein, composition of Ov-Co3O4@PPy with Co3O4 rich in oxygen vacancy defects and polypyrrole was synthesized using NaBH4 reduction and chronoamperometry. Ov-Co3O4 was synthesized while regulating the concentration of the reducing agent NaBH4 solution, and then Ov-Co3O4@PPy was synthesized by electrodeposition of PPy. The specific capacitance of Ov-Co3O4@PPy formed at an optimal NaBH4 concentration and electrodeposition time was about three times that of Co3O4 without reduction treatment and unwrapped PPy. The capacitance retention rate of Ov-Co3O4@PPy was close to 80.5% after 5000 cycles. In addition, Ov-Co3O4@PPy//AC asymmetric supercapacitor was assembled with the as-prepared Ov-Co3O4@PPy as the positive electrode material and activated carbon as the negative electrode, which yielded specific energy density up to 74.55 Wh kg−1 at 850 W kg−1 power density and a capacitance retention rate close to 110% after 10,000 cycles.