Abstract: Disclosed is a ring cutting tool for large cables including an installation component having a base and a middle support; an adjustment component at the support's bottom, the adjustment component includes an adjustment seat located at the bottom of the support, a scale component set inside the adjustment seat and a feeding component positioned inside and outside the adjustment seat; and a ring cutting component positioned at the bottom of the adjustment seat, the ring cutting component includes a drive component positioned between the base and the support, a cutting blade positioned at the bottom of the adjustment seat, and a locking component positioned inside the cutting blade. These components and the ring cutting component arrangement allow the device to automatically advance the cutting blade when cutting cable insulation, which not only reduces the cutting pressure of the device but also prevents damage to the interior of the cable.