The low energy density of supercapacitors currently limits their widespread applicability. With the development of 3D printing technology in the field of energy storage, fine electrode structures can be designed to overcome this limitation. This paper reports an ink consisting of alpha-MnO2 nanorods, reduced graphene oxide, and pluronic F127 and employed it for the extrusion-based 3D printing of supercapacitor electrodes. The 3D-printed 1-layer electrode achieved a mass-specific capacitance of 422 F g(-1) at a current density of 0.1 A g(-1), and the as-prepared full-cell supercapacitor based on such electrode, its energy density reached 19.35 Wh kg(-1), corresponding to a power density of 50 W kg(-1). The extrusion 3D printing method also allows for the fabrication of multiple electrode layers, and the 3D-printed electrodes were demonstrated as capable of practical applications such as powering LEDs and charging a mobile phone. The proposed 3D printing technology for preparing supercapacitors can quickly and economically prepare supercapacitors with special structures in large quantities, providing a method for large-scale applications of supercapacitors, and also provides some inspiration for the structure of other energy storage devices such as ion batteries.