The invention discloses an oil cooling system for a rotor-type compressor during helium compression. The oil cooling system comprises the rotor-type compressor, a cooler and a heat exchanger, wherein an oil outlet is formed in an oil pool at the lower part of the rotor-type compressor; the oil outlet is connected with an I-road inlet of the cooler through a first pipeline; an I-road outlet of the cooler is connected with an inlet of the heat exchanger through a second pipeline; an outlet of the heat exchanger is connected with an II-road inlet of the cooler through a third pipeline; an II-road outlet of the cooler is connected with a three-way pipe fitting through a fourth pipeline; and the other two ports of the three-way pipe fitting are respectively connected with an air suction hole and a cylinder. The cooling system adopts lubricating oil as a cooling medium, performs cycle operation, and sequentially cools a shell and the cylinder of the rotor-type compressor, the temperature of the rotor-type compressor during operation is effectively decreased, and the operation of the compressor is safer and more stable.