Abstract: National Nuclear Safety Administration (NNSA) requires nuclear power plants (NPPs) to improve their abilities to deal with severe accident after Japanese Fukushima nuclear accident. The severe accident management guidance (SAMG) was developed for Qinshan-Ⅰ NPP in response to NNSA. Typical severe accident sequences were simulated by using MELCOR code, according to strategy used in SAMG, to validate the effectiveness of the strategy on plant main parameters during the progress of severe accident. The results show that the progress of core damage will be terminated or delayed if actions are taken in time.