Abstract: OECD CCI-2 prototype material test was used for calculation case in this paper. By means of appropriate assumption, specific model combination and sensitive parameter optimization, MEDICIS code modeling analysis was conducted on the erosion behaviours of the reactor cavity with high gas-content limestone-common-sand concrete in homogeneous melt pool configuration. The calculation results have a satisfied agreement with the related experimental results. It was shown that the present modeling method is with fair flexibility and applicability, thus could supply the accident predictions on nuclear power plant with related modeling reference and validation basis.