Abstract: The containment responses were analyzed by using integral safety analyses code for nuclear power plant in the case of station blackout (SBO). It could be concluded that the containment failure would take place due to overpressure during SBO. If alternating current (AC) power recovers in time, the pressure and the temperature in the containment will decrease rapidly, and the containment failure doesn’t occur. In the case of AC power recovers before RPV rupture, the integrality of RPV might be kept. In the cases of AC power recovered after RPV rupture, the steam concentration in the containment decreases sharply, the hydrogen concentration increases accordingly, which results in the increase of the hydrogen risk.