A dynamic environment can radically change the improvement of software for information system development. The change related to the time, cost, effort and quality. This situation forces the system to improve its reusability in terms of commonality and variability business processes. In order to response to it, we develop mechanism for system architecture that based on technical and business process alignment approach. We proposed system architecture that characterizes by business process commonality and variability. The proposed system architecture consists of busines process layer, user interface layer, application layer, integration layer, legacy business process layer and data layer. Variant of business processes and tasks can be embedded to one another. Beside that, it can support substitution and replacement among part of business processes and tasks that make possible for sharing parts among entitites. The entitiy can choose suitable parts of common and specific business processes in dynamic environment. Hence, the system architecture can minimize time, cost, effort and improve software quality for information system.