The invention belongs to the technical field of freeze preservation, and provides a quality guaranteeing method using living body cryopreservation. The quality guaranteeing method comprises: A, pretreatment of a material: removing soil and debris from the surface of fresh plant rhizome; B, cooling dewatering treatment: carrying out gradient cooling treatment on the fresh plant rhizome obtained inthe step A under a ventilation condition to obtain a low-temperature dewatered plant rhizome with a temperature of below 0 DEG C, wherein the slowest cooling rate of less than 1.0 DEG C/d is used whenthe gradient cooling treatment achieves a temperature of 4 DEG C; C, water spraying ventilation preservation: maintaining the constant temperature of the low-temperature dewatered plant rhizome obtained in the step B, providing air to the low-temperature dewatered plant rhizome, and periodically spraying with water mist to form a thermal insulation water supply ice layer on the surface; and D, temperature increase water supply treatment: under a ventilation condition, carrying out gradient heating treatment on the frozen living plant rhizome obtained in the step C to obtain the quality guaranteeing plant rhizome. With the method of the present invention, the problems that the traditional refrigeration technology cannot achieve the long-term fresh-keeping and preservation of plant rhizomeand the re-cultivation after long-term refrigeration are solved.