The invention provides a pressure-maintaining
coring device. The pressure-maintaining
coring device comprises an outer
pipe unit, an inner
pipe unit and an anti-twist-off
assembly, wherein the outer
pipe unit comprises an outer cylinder and a
drill bit; a first containing cavity is formed in the outer cylinder. The inner pipe unit comprises an inner cylinder, a shock-proof
assembly, a
cut-off
assembly, a sealing assembly and a clamping assembly. The shock-proof assembly is used for abutting against the outer wall of the
rock core entering the second containing cavity so as to eliminate the vibration effect of the inner cylinder on the
rock core. And the
cutting assembly is used for
cutting the
rock core entering the second accommodating cavity. And the sealing assembly is used for automatically closing after the
cutting assembly cuts the rock core and drives the
cut rock core to move upwards in the inner cylinder, so as to seal the second accommodating cavity. The clamping assembly is used for clamping the rock core in the second containing cavity after the rock core is
cut. The anti-twist-off assembly is used for eliminating twisting force transmitted from the outer cylinder to the inner cylinder. The pressure-maintaining
coring device provided by the invention can effectively protect a rock core, can effectively reflect a real underground condition, and is good in pressure-maintaining coring effect and relatively high in practicability.