The invention discloses a self-evaporation technology of steam condensate, belonging to the technical field of alumina production. The respective self-evaporation technology of new steam condensate and secondary steam condensate aims at the alumina production process and are as follows: in the working procedures of desiliconizing crude liquor and evaporating, autoclaving and stripping mother liquor, the new steam condensate and the secondary steam condensate enter respective self-evaporation systems for self evaporation, and secondary steam by the self evaporation preheats raw liquor; last-stage new steam condensate returns to an electric station to be used as boiler supplement water, qualified last-stage secondary steam condensate after being detected returns to the electric station to beused as boiler supplement water, and unqualified last-stage secondary steam condensate is processed by the red mud washing working procedure. The influence of the alkaliferous secondary steam condensate because of unstable water quality can be lessened so that the new steam condensate can be returned to the electric station to be used as the boiler supplement water to reduce the cost for desalting and deoxidizing newly supplemented water, balance the pressure of the condensate self-evaporation equipment and simplify the manufacture of the condensate self-evaporation equipment.