The invention discloses a grouting water sealing and reinforcement construction process capable of realizing a draining and plugging combined effect for underground water in a tunnel. The grouting water sealing and reinforcement construction process includes steps of (1), arranging grouting pipes from the inner side to the outer side of the tunnel, simultaneously arranging drain pipes matched with the grouting pipes in the tunnel, connecting the drain pipes with a vacuum pump so as to locally pump the water; (2), diluting sodium silicate of raw grout 39Be' to obtain grout 28Be', mixing TGRM grouting materials with cement according to a proportion of 1:3 to obtain second grout, mixing the grout 28Be' with the second grout according to a proportion of 1:1 to obtain liquid A, diluting sodium silicate of raw grout 39Be' by water to obtain grout 30Be', diluting strong phosphoric acid by water according to a proportion of 1:6 to obtain diluted phosphoric acid, and mixing the grout 30Be' with the diluted phosphoric acid according to a proportion of 1:1 to obtain liquid B; (3), alternately filling the liquid A and the liquid B into reinforcement soil layers outside an excavation range of the tunnel via the grouting pipes to complete grouting for the periphery of the tunnel; and (4), alternately filling the liquid A and the liquid B into a 1.5m range of the periphery of an excavation face via small pipes. The grouting water sealing and reinforcement construction process has the advantages that 'draining' and 'plugging' are combined and work along both lines in the construction process, accordingly, the underground water is prevented from diffusing and permeating to feeble grouted positions, the tunnel construction difficulty is reduced, and the construction safety degree is increased.