The invention relates to the technical field of heat exchange, and relates to a refrigerant cooling system with high temperature stability. The system comprises a variable-frequency compressor, a condenser, a radiator and a phase-change energy storage unit, wherein the radiator is in contact with heat generating components, and the phase-change energy storage unit is arranged on the radiator; thephase change energy storage unit comprises a high-temperature phase-change material, a medium-temperature phase-change material and a low-temperature phase-change material which are not less than three phase change points in different temperature areas; the high-temperature, the medium-temperature and low-temperature phase-change materials are made of non-metal materials and are correspondingly and independently arranged on the radiator; the phase-change temperature of the medium-temperature phase-change material is the working temperature of the radiator; and a refrigerant pipeline and a coldmedium flowing through the refrigerant pipeline are arranged in the radiator. According to the refrigerant cooling system with high temperature stability, the refrigerant cooling technology and the phase change energy storage technology are organically combined, phase change materials with three or more than three phase change points in different temperature zones are used, multiple temperature buffering and temperature control signals are provided, the temperature runaway risk is reduced, and the problem that a traditional refrigerant cooling system is insufficient in temperature stability when the loss is changed is solved.