The invention relates to a three-dimensional porous nitrogen-doped hollow carbon nanosphere, and a controllable preparation method and an application thereof. The particle size of the product is 100-150 nm, the shell of the hollow carbon nanosphere is evenly provided with micro-pores with a diameter of 0.7-2 nm, and the cavity diameter of the hollow carbon nanosphere is 30-50 nm. Compared with theprior art, the preparation method has the following advantages: 1) the synthesis process is simple, so the hollow nanosphere structure can be obtained by one-step polymerization, and the cost is low;2) the product has a uniform size, intercommunicated micropores and a hollow structures, so ions can be easily adsorbed, stored and transferred; 3) in-situ doping of nitrogen atoms can effectively improve the electric conducting property and the electrochemical properties of the material; and 4) the in situ nitrogen-doped three-dimensional porous carbon nanosphere has an excellent adsorption property, can adsorb a large amount of electrolyte ions due to rich micro-porous voids, and has a high specific capacity, excellent rate performances and an excellent cycle stability when used as a supercapacitor electrode material.