A facile, one-step, soft chemistry approach is developed to synthesize ClO4-doped polypyrrole coated Na1+xMnFe(CN)6 composite as a cathode material (NMHFC@PPy) for SIBs. PPy plays multiple important roles in the composite. First, PPy serves as a conductive coating layer which can increase the electronic conductivity of NMHFC to improve the rate capability. Second, PPy can act as a protective layer to reduce the dissolution of Mn in the electrolyte to improve the cycling performance. Finally, the PPy doped with ClO4 - can act as active materials to increase the capacity of the composite. NMHFC@PPy shows high energy density (428Whkg-1), enhanced cycling performance (67% capacity retention after 200 cycles), and excellent rate capacity (46% capacity for 40C rate).