Abstract: In order to ensure that the radioactive consequences of China Engineering Test Reactor meet the requirements of safety supervision under the severe accident condition and that no out-of-site intervention measures are required, it is necessary to design the discharging scheme of radioactive substances under the severe accident condition. This paper mainly analyzes the leakage rate, the air exhaust volume and the sealed mode, and studies the change rules of radioactive consequences. The results show that the airtight building leakage rate of 2%/d and the discharging scheme of "the emergency ventilation system is closed during the preliminary stage and opened after the 8 h sealed time" should be adopted for China Engineering Test Reactor.