Nowadays, global competition has grown to the extent that simple reliance on internal performance and firm strengths will not lead to survival and growth. Companies use each other's exploitable common aspects using the composition tools. Economics knows useful the dynamics of the resource composition tool as well as conducting buying and selling transactions and merger and acquisition by companies. In fact, one of the strategies of companies is their merger and acquisition strategy. The most important reasons for adopting this strategy are gaining synergies, increased equity of shareholders, scale and environmental savings, increased market share, increased research and development capacity, company growth and reduced risk to realize the company's most important goal of creating value and increasing the wealth of equity holders. According to the above mentioned items in this research, we seek to evaluate the financial performance and ranking of companies accepted in the Tehran Stock Exchange before and after the acquisition. This study is an applied research in terms of the purpose and a post event research in terms of data collection method. The variables studied in this research are total assets returns, return on equity, stock revenues, economic value added, market value added, return on investment cash flows, and cash value added. The ranking performed by the fuzzy AHP method shows that the ROI is of higher importance and weight, and return on investment cash flows index has the least weight; then, 10 companies in the industries of minerals, automobiles and parts manufacturing, materials and pharmaceutical products have been ranked. The rankings show that corporates ratings is differented before and after the acquisition and TOPSIS and SAW showed different results.