[en] Steam generator tube rupture (SGTR) accident is a significant design basis accident which shall be analyzed in PWR nuclear power plant safety analysis reports. Thermo-hydraulic analysis of SGTR accident for licensing has been done using a specific code entitled LOFTTR2. To validate the applicability of RELAP5 for AP1000 SGTR accident, a RELAP5 model for AP1000 is established and used to assess this accident. Results show that both the accident progression and the doses result of RELAP5 calculation correspond well with that in Safety Analysis Report. Thus, RELAP5 and RELAP5 model of AP1000 can apply to other SGTR type analysis. (authors)