A navel technology for resistance spot welding with interventional powder thermite was proposed, which is characterized with energy saving and high efficiency. The influences of the interventional powder thermite ZnO+Al upon the nugget formation, the microstructure and the mechanical property were studied in the resistance spot welding of 2024 aluminum alloy. The results indicate that the powder thermite ZnO+Al can effectively increase the dimension of the nugget and the dentrite region with the extra help of the heat of the metallurgical reaction from the powder thermite ZnO+Al. The ZnO+Al addition increases the heterogeneous nucleation in the nugget and prompts the appearing of a large scale constituent supercooling in the solid-liquid interface front during the process of solidification, which makes the distribution of equiaxed grains more uniform and refines the dentritic bundles of the equiaxed grains in the nugget. According to the aforementioned facts, the tensile-shear strength of the nugget is improved. The experimental results show that the spot strength can increase by over 28%~200% in the range of experiments with the help of the ZnO+Al addition.