A novel three-dimensional (3D) porous MnO2 film has been deposited onto a foamed nickel with another 3D structure by a hydrothermal method using potassium permanganate and sodium dodecylsulfate under neutral condition. Characterized by powder X-ray diffraction, scanning electron microscopy and thermal analysis, so formed 3D structure film is composed of nanosheets or nanofibers and has an amorphous and hydrous nature. The high specific capacitance of 241 F g-1 is observed at the current density of 1 A g-1, investigated by means of cyclic voltammetry and constant current charge-discharge cycling in 1 M Na2SO4 aqueous solutions. The film shows a good reversibility, power characteristics and cycling stability. It is promising for supercapacitor application.