Low-temperature storage device and control method thereof

The invention provides a low-temperature storage device and a control method thereof, and relates to the technical field of low-temperature storage. The low-temperature storage device is used for solving the problem that a load of a compressor is large when a refrigeration system of an existing low-temperature storage device starts to run, and a protector is easy to trip. The low-temperature storage device comprises a fourth connecting branch, a control valve, an expansion container, and a detecting device, wherein one end of the fourth connecting branch is connected with an air outlet of a liquid distributor, and the other end of the fourth connecting branch is connected with an air suction port of the compressor; the control valve is arranged on the fourth connecting branch, and the expansion container is connected with the fourth connecting branch on the downstream side of the control valve; and the detecting device is configured to detect a pressure value in the fourth connecting branch located on the ups