When building some kinds of IT systems, security-related requirements must be considered. It is essential that not only the customer's requirements for software or systems functionality should be satisfied but also the security requirements imposed on the software or systems development should be effectively analyzed and implemented in contributing to the security objectives of customer's requirements. Though the customer's requirements must be implemented to software or systems perfectly, but these are not sufficient. The secure software or systems may be implemented by not only applying security products but also considering security requirement appended to customer's requirement. In this paper, we propose a security engineering based approach considering security when developing software or systems based on System Block Model.