The invention relates to the technical field of
liquid nitrogen refrigeration, in particular to a
liquid nitrogen refrigeration-based ultralow-temperature precise constant-temperature device which comprises a
liquid nitrogen tank and a constant-temperature tank, an inner box is arranged in the constant-temperature tank, an outer ring body is arranged on the outer surface of the constant-temperature tank, an air suction
assembly is arranged on the outer surface of the outer ring body, and an exhaust
assembly is arranged on the outer surface of the constant-temperature tank. A
nitrogen tank is arranged at the end, away from the constant-temperature tank, of the exhaust
assembly, a butt-joint
pipe is arranged between the liquid
nitrogen tank and the constant-temperature tank, and a butt-joint assembly is arranged on the outer surface of the butt-joint
pipe. Compared with the prior art, the constant-temperature tank and the outer ring body are communicated through the air exhaust assembly, a motor is used for driving a rotary disc to rotate to drive a shifting block to pull a strip-shaped plate to move up and down, the strip-shaped plate drives a first one-way valve to move up and down to extrude or stretch the upper part and the lower part of a corrugated
pipe, and the outer ring body is filled with
nitrogen in the constant-temperature tank; and the effect of cooling the outer surface of the constant-temperature tank is achieved, the gasification speed of liquid nitrogen is reduced, and the energy-saving effect is achieved.