One of the important issues of today's world is efficiency measurement of different organizations and the comparison between their units. On the other hand, banks play pivotal role in improvement of economic signals in each country. Therefore, considering this role and the number of banks in Iran, efficiency measurement of banks becomes important. The Main goal of this paper is studying the effects of considering the importance of data in the DEA model. This paper accomplished in five stages. The main stages of this paper include recognition and measuring the importance of effective factors on bank efficiency, measuring the bank branches efficiencies and analyzing the effects of using importance of data in DEA technique. Therefore, at first, the conceptual system of efficiency evaluation has been defined and after measuring the importance of data in efficiency of bank branches using Fuzzy Topsis technique, efficiency of branches formulized and calculated in the context of DEA models. Ultimately for analyzing effects of using importance of data, efficiency of branches recalculated without recognizing the results of Fuzzy Topsis. Results show that using the importance of data can make the efficiency measurement of bank branches more precise and so increases it's validity.