Recently, the LISI(Level of Information System Interoperability) model has been used to measure level of interoperability in the Ministry of National Defense. This study is proposed for improvement of interoperability level measurement method. The MND has been devoting a lot of effort to ensure defense weapon system interoperability. They enacted related regulations and developed SITES for measuring the level of interoperability. However, the LISI model has problems with using just only DITA and applying MND-AF based on Architecture development. To overcome these problems, this paper proposes how to apply reference model to LISI Model and how to apply LISI Model to MND-AF architecture development.