The invention relates to a high-voltage iron tower grounding device, and particularly to a colloidal graphite grounding electrode. The colloidal graphite grounding electrode comprises a graphite flexible rope and is characterized in that the graphite flexible rope is mounted in a colloidal graphite block; connecting ends for connecting with lines extend out of two ends; the colloidal graphite block has an elongated block-shaped structure; the colloidal graphite block is obtained through mixing colloidal graphite and water and solidifying; and the graphite flexible rope is in a coiled state in the colloidal graphite block so that voltage is uniformly transmitted. The colloidal graphite grounding electrode has advantages of high electric conductivity, high absorption, high plasticity, no soil environment, long service life, high corrosion resistance, simple production, stable grounding resistance, high binding ability with soil, and low contact resistance.