The invention discloses a nitrogen doped porous active carbon material, which is prepared by burning a carbon precursor prepared from sago cycas, a nitrogen source, and an alkaline inorganic substance. The specific surface of the material is in a range of 1136 to 2628 m<2>/g, and the average aperture is in a range of 1.17 to 2.11 nm. The preparation method comprises the following steps: step one, washing the leaves of sago cycas by water, drying the leaves, grinding the leaves, and burning the leaves to obtain a carbon precursor; step two, mixing the carbon precursor, the nitrogen source, and the alkaline inorganic substance, soaking, drying, burning, and carrying out activation to obtain a nitrogen doped porous active carbon material; and step three, soaking the nitrogen doped porous active carbon material in an acid solution, washing, filtering, drying, and grinding to obtain the final nitrogen doped porous active carbon material. When the material is used as the electrode material of a super capacitor, and if the current density is 1 A g<-1>, the specific capacitance is in a range of 266 to 351 F g<-1>. Leaves of sago cycas are taken as the raw materials, the application range is enlarged; and the material has a wide application prospect in the fields of porous materials and super capacitor.