The invention discloses a casing material for horizontal valve pipe grouting for an overlaying water-rich gravel layer above a shield top line. The casing material is characterized by comprising raw clay slurry, cement, silica fume, a water reducer, calcium formate and inorganic lithium salt. The specific gravity of the raw clay slurry is 1.20-1.35, the mass ratio of the raw clay slurry to the cement is 0.3-1.5, the mass ratio of the cement to the silica fume is (10:1)-(20:1), the addition amount of the water reducer is 0.1%-3% of the mass of the cement, the mixing amount of calcium formate is0.5%-0.8% of the mass of the cement, and the mixing amount of the lithium salt is 0.01%-2% of the mass of the cement. The casing material is easy to control in setting time, good in plugging effect and capable of meeting the requirement of repeated horizontal positioning grouting.