Software development based on the software product-line can develop software products more easily and fast by reusing the developed core assets. One of key issues of software product-line is to handle variability between product families. That is, the variation management for software product-line decides the success of software development. There are considerable researches relating to model the variability in software product-line. However, the existing researches do not explicitly define artifacts and any relevant relationships between them used in each process. Therefore, in this paper, processes and artifacts of each process to manage uniformly variability over the life cycle of software product-line are proposed. Furthermore, in order to show how to apply those into a specific domain, especially electronic medical record (EMR) system, case study is presented.