The invention discloses a lifting type sample preparation technology for a tri-axial sample of undisturbed soil. The technology comprises the steps as follows: firstly, according to characteristics ofa soil sample, the hardness of the soil sample is judged, and the cutting rotation speed of a cutting mechanism is determined; then the soil sample is placed on a lifting mechanism and can be drivenby the lifting mechanism to rise, the soil sample rising gradually is cut through rotation of a cutting blade of the cutting mechanism, and preliminary preparation of the tri-axial sample is completed; and finally, the height of the lifting mechanism is reduced, the sample is taken out and is treated according to the required height, and the sample preparation is completed. According to the technology, the problems that operation steps are tedious, the influence caused by the operation proficiency of sample preparation persons is large, the sample preparation efficiency is low, the disturbanceto the soil sample is large, the success rate of sample preparation is not high and the like in existing sample preparation processes are solved.