Objective To search for the most appropriate subzero nonfreezing temperature,and explore the effect of subzero nonfreezing preservation of rat kidney by comparing with the kidney preservation with conventional temperature (4 ℃,0 ℃) and freezing temperature (-4 ℃).Method The thermocouple probeand the temperature data logging device were used to detect the temperature decreasing curves in different parts of the rat kidney and determine the freezing point of the kidney.The perfused kidneys in rats were removed and put into the sterile tubes containing 2.5 mL hypertonic citrate adenine.Following 6 group were set up:-0.8 ℃ group (subzero nonfreezing),-0.5 ℃group (subzero nonfreezing),0 ℃ group (zero nonfreezing),-4 ℃ group (control group),-1 ℃group(subzero freezing)、-4 ℃ group (subzero freezing).After the cryopreservation for 24 and 48 h,the preservative fluid was harvested for measurement of the contents of LDH and AST,and the paraffin sections from the upper pole of the kidney were made for observation of the pathological changes and apoptosis.Result The freezing temperature of kidney was-1℃ and the most appropriate subzero nonfreezing temperature for preserving the rat kidney was-0.8 ℃.Subzero nonfreezing significantly inhibited the basal metabolic rate of the histiocytes,reduced the contents of LDH and AST released due to the membrane damage,and decreased the apoptosis rate [48 h:-0.8 ℃ (40.1 ± 7.0) ％ vs.4 ℃ (47.1 ± 7.6) ％].Under the light microscope after preservation for 48 h,the pathological changes in-0.8 ℃ group were less than in 4 ℃ group.Conclusion Compared with the organ preservation in conventional temperature (0 ℃-4 ℃),the subzero nonfreezing (-0.8 ℃) can further inhibit the basal metabolic rate of histocytes obviously,reduce its energy consumption,and lower the apoptosis caused by low temperature damage.