With developing computer and communication technologies, the concept of CALS system has been popular not only to military but also to commercial industries. The security problem is one of the most critical issues to construct CALS infrastructure. The CALS system needs some security functions such that data confidentiality, integrity, authenticity, availability, and non-repudiation. This paper proposes a security architecture model in CALS. The security architecture model is composed of 5 submodels such that network security model, authentication and key management model, operation and audit model, integrated database security model, and risk analysis model.