The invention relates to a grounding grid connection testing tool. The grounding grid connection testing tool is characterized by comprising a connecting column which is composed of a section of cylinder (2) and a section of cone (1), one end of the cylinder (2) of the connecting column is fixedly connected with an insulating rod (5) through a connecting base (4), filing lines or filing teeth are arranged on the surface of one end of the cone (1) of the connecting column, and in addition, at least one binding post (3) is arranged on the surface of one end of the cylinder (2). The trial use proves that after the tool is adopted, rapid grinding and testing tool connection can be achieved, and the safety of work is ensured. Meanwhile, due to the fact that the grinding face of grounding flat iron is remarkably narrowed, the phenomena that the exposed grounding flat iron is corroded and cracks can be effectively prevented, and the attractiveness and the service life of the grounding flat iron can not be influenced. The average time of the single-interval grounding connection test is shortened to about 2.75 minutes from the existing about 6 minutes, and the efficiency of the grounding grid connection test work is improved to a great extent.