Abstract: To study the typical small break loss of coolant accidents (SBLOCAs) on the Advanced Core-cooling Mechanism Experiment (ACME), which was the first integral test facility on passive core cooling system of nuclear power plant in domestic, the experimental and numerical analyses were carried out. The analysis results show that the accident chronology and major thermalhydraulic phenomena of typical SBLOCAs on ACME are as to be expected, and the numerical results of RELAP5 model and experimental results are highly consistent. The interfacial drag model in rod bundle geometry has a great effect on reactor core collapsed level calculation, and different models adopted during different accident processes will guarantee better match between calculation values and experimental values.