The invention discloses a support and anti-seepage structure of a tunnel high-pressure water-rich solution cavity section, which comprises a double-layer initial support, first-layer waterproof structure and double-layer secondary lining which are sequentially arranged in the inner ring of the high-pressure water-rich dissolving cavity section, an anti-seepage isolating section arranged at two ends of the high-pressure water-rich solution cavity section, and the double-layer secondary lining is composed of a first layer secondary lining and a second layer secondary lining, the construction seams of the first layer secondary lining and second layer secondary lining are staggered, the anti-seepage isolating section uses an initial support and a secondary lining, and the secondary lining is closely attached to the initial support. Meanwhile, the invention also discloses a construction method of the support and anti-seepage structure tunnel high-pressure water-rich solution cavity section.Not only can that the structural strength of the solution cavity section is sufficient to resist the high water pressure of the solution cavity be ensured, but also the damage to the normal support section other than the solution cavity section can be prevented when karst underground water and mud in rush happen in the solution cavity.