Abstract: Domestic nuclear power projects such as AP1000, EPR and HPR1000 have used the level 2 PSA source terms for the emergency input, but there is no clear operational methods for the division of level 2 PSA release categories and the selection of representative accident sequences for each release category, and further research is required. Comparing the level 2 PSA release categories and the selection of representative accident sequences for each release category of domestic advanced nuclear power plants, taking a domestic generation  = 3 * ROMAN * MERGEFORMAT III advanced pressurized water reactor nuclear power plant as an example, the source terms were calculated for 4 different accident sequences that selected from a release category based on frequency and consequences. The results show that the source results of different accident sequences are quite different. It is recommended that the release category be divided into application-oriented and iterative according to the analysis purpose, and multiple accident sequences should be selected for the same release category for comparative analysis to demonstrate reasonable release categories and representativeness of accident sequences.