The invention relates to an over-temperature protection cooling system for the condensate water of a high back pressure heat supply unit. The over-temperature protection cooling system comprises a condenser and a condensate water precision treatment device, wherein a condensate water heat exchanger is arranged between the condenser and the condensate water precision treatment device; and the condensate water is introduced to the condensate water heat exchanger from one end, and heat supply network return water is introduced to the condensate water heat exchanger from the other end to serve as cooling water. According to the over-temperature protection cooling system for the condensate water of the high back pressure heat supply unit, the structure is simple, the investment is low, the effective control over the condensate water temperature of the high back pressure heat supply unit is realized, the heat supply network return water is adopted as cooling water, the heat absorbed by the system is fully utilized, that is, the condensate water is utilized to heat part of the heat supply network return water, the heat loss is reduced, the energy is saved, and the consumption is reduced.