Normal temperature assembled ultralow temperature run centrifugal compressor

The utility model relates to an ultralow temperature centrifugal compressor, in particular to a normal temperature assembled ultralow temperature run centrifugal compressor. The centrifugal compressor comprises impellers, a main shaft, an isolating sleeve and a balance disc, wherein multiple stages of forward impellers and multiple stages of reverse impellers are arranged on the main shaft; the balance disc is arranged on the main shaft between the forward impellers and the reverse impellers; the isolating sleeve sleeved on the main shaft is arranged between every two adjacent impellers in the forward impellers; and the isolating sleeve sleeved on the main shaft is arranged between every two adjacent impellers in the reverse impellers. The centrifugal compressor can be assembled at the normal temperature of 25 DEG C, the temperature of a medium inlet is ultralow (-100 DEG C), and a unit has high mechanical property and stability during normal temperature assembly, test run and low temperature running.