The evolution of alpha-MnO2 from hollow cubes to hollow spheres was achieved by using MnCO3 as the template. The as-obtained alpha-MnO2 crystals were characterized by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET). The as-synthesized alpha-MnO2 hollow cubes (with the side length of about 2 lm) and hollow spheres (with the diameter of about 2 lm) were uniform particles. The as-prepared alpha-MnO2 hollow spheres have a large specific surface area (417 m(2) g(-1)). Aprocess has been proposed for the evolution of MnCO3 templates from cubes to spheres. Then, the evolution of alpha-MnO2 was achieved by two-step mechanism with the treatment of previously obtained MnCO3 templates. Cyclic voltammetry (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) measurements were used to characterize the electrochemical performances of the as-synthesized alpha-MnO2. The initial specific capacitance at a current density of 1 A g(-1) of the as-prepared a-MnO2 hollow spheres is 203 F g(-1), which is higher than that of alpha-MnO2 hollow cubes (152 F g(-1)). In addition, the alpha-MnO2 hollow cubes retain 93% and the alpha-MnO2 hollow spheres retain 80% of the initial specific capacitance after 2000 charge/discharge cycles at 2 A g(-1). The alpha-MnO2 hollow spheres-based supercapacitors exhibit 38.7 W h kg(-1) at a power density of 1000 W kg(-1) and maintain 7.8 W h kg(-1) at a high power density of 10028 W kg(-1).