The utility model belongs to the technical field of nuclear power station nuclear power engineering, the concretely relates to safe dismouting that can guarantee mechanical seal graphite sound ring member alleviates maintenance person person's intensity of labour, improves work efficiency, reduces collective dose value nuclear reactor cooling agent pump mechanical seal unit dismouting device, sealring gland (2) and base (3) including gland nut (1), machine, wherein base (3) are the disc, and centre of a circle position has a screw rod immediately, and the screw rod can pass the machine and seal ring gland (2) center hole, and the machine seals ring gland (2) top and still is equipped with gland nut (1), 1 the utility model discloses a nuclear reactor cooling agent pump mechanical seal unit dismouting device application method is simple, can be with nuclear reactor cooling agent pump mechanical seal unit dismouting work simplification, and the dismouting in -process need not quite to do all can dismouting graphite sound ring etc. And easily decreases the vitals.