The invention aims to provide a three-dimensional heat source with long life and high electro-thermal conversion efficiency. The three-dimensional heat source comprises a heating element and at least two electrodes, wherein the heating element comprises a substrate and a plurality of carbon nano tubes distributed in the substrate; the electrodes are arranged at intervals and are respectively connected with the heating element electrically; the heating element forms a hollow three-dimensional structure and the carbon nano tubes in the heating element form at least a self-supporting carbon nanotube structure. The three-dimensional heat source can be used for manufacturing pipelines in plants, heating furnaces in laboratories or electric ovens in kitchens, etc.