The purpose of this research is to find out and to analyze internal and external environment factors that influence in determining the company's strategy, in this case PT. Telkomsel Malang Branch, also to find out and explain marketing strategy used by PT. Telkomsel Malang Branch to achieve competitive advantage. The type of research used in this study is descriptive research method, focusing on corporate environment consisting of internal and external environment. Data analysis method used in this research are External Factor Evaluation matrix (EFE), Internal Factor Evaluation matrix (IFE), SWOT matrix, Internal External (IE) matrix, and QSPM matrix. The results of the analysis EFE matrix produce values 2,59 and analysis IFE matrix 3,56. According to analysis position company IE matrix is in cell IV, namely grow and build. The result from this research shows the appropriate strategy for PT. Telkomsel Malang Branch is intensive strategy, which consisting of market penetration, market development, and product development. This strategy seek to to expand their market share region and directing existing resource to achieve bigger objective and gain.