Cooling device and method for un-shelving to-be-cooled device in cooling device

The invention provides a cooling device and a method for un-shelving a to-be-cooled device in the cooling device. The cooling device cools each to-be-cooled device through a cooling liquid, wherein the cooling device comprises a cabinet body and buoyancy devices connected to the cabinet body; the cabinet body is used for accommodating each to-be-cooled device. When the to-be-cooled device is gradually placed into the cooling device, the cooling cabinet automatically sinks to ensure that all the to-be-cooled devices are immersed by the cooling liquid, and the operation is simple and convenient.When the to-be-cooled device is required to be un-shelved, only a slightly small tension force needs to be applied to the cabinet body, so that the to-be-cooled device on the uppermost layer is allowed to float out of the liquid surface of the cooling liquid, then the to-be-cooled device on the uppermost layer is moved out of the cabinet body, the cooling liquid does not need to be completely poured out, and the un-shelv