Design and fabrication of ternary hybrid material is an effective method to promote the performance of supercapacitor electrode materials, because hybrid material does not only benefit from the advantages of each component but also utilizes the synergetic effect between them. Reduced graphene oxide (rGO)@MnO₂@PEDOT-PSS (poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate)) ternary material is designed and fabricated. Electrochemical tests reveal that sample GMP20 (rGO 8 wt%, MnO₂ 72 wt% and PEDOT-PSS 20 wt%) exhibits the highest high specific capacitance of 217.8 F g⁻¹, excellent rate capability and the best cycle stability with 93.7% capacitance retention after 1500 cycles at 2 A g⁻¹. To investigate the synergetic effect, electrochemical impedance spectroscopy (EIS), complex capacitance analysis and complex power analysis are employed. The mass ratio of components has a great influence on supercapacitve performance of the hybrid electrode by affecting the synergetic effect. Results show that GMP20 has well matched relaxation time, smallest impedance modulus and time constant, thus it fully utilizes the synergetic effect and exhibits excellent supercapactive performance.