The invention discloses a sand soil sampling device for grouting model test and a method. The device comprises three parts: a connected barrel body, bearing frames and rotary cutterheads. The connected barrel body is a symmetrical structure, and is provided with holes along the wall, the internal space is the size of a standard compressive test piece, after sleeving joint with the two bearing frames stretching into the internal space from the upper and lower ends, end threads are utilized for screwing up. Cavities are reserved inside the bearing frames for accommodating the rotary cutterheads,the middle parts are equipped with internal threads, and the lower parts are equipped with circumferential trapezoidal beams to achieve cutting and structural stability. The rotary cutterheads have an embedded double-layer structure, and can rotate freely, the upper layer is used for fixing and pressure-bearing, and the lower layer is used for cutting soil. At the same time, the invention also discloses a test method of the system. The device provided by the invention can ensure continuous strain of model test sand soil, the sampled test piece is smooth overall and can be subjected to compression test directly, the device has the characteristics of good self-integrity, simple components and easy operation, and is convenient for batch making.