The invention discloses a remoulding soil sample preparation device, comprising a base, a sample containing mould, a compacting instrument, a positioning device, a clamping rod and a bearing plate, wherein the sample containing mould is fixedly arranged on the base; the positioning device is sheathed on the clamping rod, is vertically moved along the body of the clamping rod, is rotated by a set angle along the horizontal direction, and is clamped on the clamping rod by a clamping mechanism to position the height of a sample; the compacting device and the bearing plate are respectively and fixedly arranged at both ends of the clamping rod; the diameter of the compacting device is matched with the inner diameter of the sample containing mould, the inner diameter of the positioning device is matched with the size of the clamping rod, and the outer diameter of the positioning device is greater than the outer diameter of the sample containing mould; after the compacting device compacts the sample, the bottom end surface of the positioning device is connected with the top end surface of an opening of the sample containing mould to prepare the sample; by changing the height of the sample positioned by the positioning device on the clamping rod, soil samples with different heights can be prepared. The remoulding soil sample preparation device has the advantages that the structure is simple, the operation is convenient, the accuracy is higher, the suitability is wide, and the number of sample compacting layers and the sample compacting height of each single layer can be flexibly changed according to different heights of the prepared samples.