The invention discloses slurry for construction of a pebble-layer underground continuous wall. The slurry is characterized by being prepared from the following raw materials in parts by weight: 120 to 130 parts of sodium-based bentonite, 3 to 4 parts of basalt fiber, 40 to 50 parts of CMC (Carboxyl Methyl Cellulose) and a proper amount of saline water. Components and ratios of the slurry are designed to obtain the slurry, which is especially suitable for groove formation and wall protection of the pebble-layer underground continuous wall in Southwest regions, and the slurry has the advantages of proper density, easiness of being precipitated and proper mud cake thickness; residues can be suspended and the residues can also rapidly sink when the residues are circulated in the slurry, so that the technical effect which cannot be realized by existing slurry is realized.