A rotary table mechanism capable of guaranteeing sequential rod unloading relates to the field of agricultural facilities and is applied to a grain sampling device, the grain sampling device comprisesan upright post, a drill bit is fixed at the upper part of the upright post, and the rotary table mechanism comprises a mounting seat arranged at the lower end of the upright post; the first supporting plate is fixed to one side of the mounting base, a hollow rotary table is fixed to the upper portion of the first supporting plate, a driving motor is mounted on the lower portion of the first supporting plate, and the axis of a center hole of the hollow rotary table and the axis of a drill bit are collinear; and the second supporting plate is fixed to the upper portion of the hollow rotary table, and a clamp body is fixed to the upper portion of the second supporting plate. The device is simple in structure, in the rod disassembling process, the clamp body on the upper portion of the hollow rotary table is used for clamping the sampling rods, the clamp body is matched with the drill bit on the upper portion of the stand column, the assembled sampling rods can be rapidly disassembled through reverse rotation of the clamp body and the drill bit, and the rods are successfully disassembled in sequence.