The invention discloses an air pressure cabin opening pressure-maintaining material for slurry shield. The air pressure cabin opening pressure-maintaining material is composed of a component A and a component B, and the component A comprises, by mass, 98.5%-99.8% of nanometer silica gel solution, 0.1%-0.5% of plasticizer and 0.1%-1% of stabilizer; and the component B comprises, by mass, 90%-97% of chloride ion solution and 3%-10% of polymeric dispersant, wherein the molar ratio of silicon dioxide in the component A to chlorine ions in the component B is not less than 25:1. According to the air pressure cabin opening pressure-maintaining material for the slurry shield, slurry is added for reaction, so that consistency of the slurry is risen, the wall cling property of the slurry is improved, cohesion of formed slurry film is improved, the air tightness is better, and stability of an excavation surface in the process of entering cabin under pressure in the special section is ensured.