The invention relates to a sample-making device for soil quick triaxial test and a sample-making method thereof. The sample-making device comprises a sample-beating cylinder and a sample-beating device, wherein the sample-beating cylinder comprises a base, a three-section mould, a lower clamp, an upper clamp and a protective cylinder; the sample-beating device comprises a power transmission plate, a compact hammer, a guide bar, a stopper; the base of the sample-beating cylinder is a double-faced base with one face of the central part of the base is a circular fixed groove, the other face of which is a circular fixed groove with a circular hole at the center; the three-section mould is composed of three circular-arc metal sheets with a central angle of 120 DEG. The sample-making method comprises: fixing the guide bar on the base, laminatedly compacting the soil according to the required dry density, sealing the central hole of the base with clay after being compacted, laminatedly pouring sands into the central cylinder hole and compacting the soil according to the required density, finally sealing the upper hole of the cylinder hole with clay. The invention has simple use, convenient operation, testing time saving, good effect for making uniform, standard sand-core cylinder, can be popularized in the field of soil test technique.