The South Khorasan province is located in eastern Iran. Identifying potential geothermal zones is a pre-requisite for any Thermal power plant and recreation center project. Geothermal exploration involves a high degree of uncertainty and financial risk, and requires reliable exploration data to constrain development decisions. The present study focuses on identifying the potential zones of geothermal in South Khorasan. In this research, 5 effective factors in potential geothermal such as Land surface temperature (L.S.T), Lithology, Surface evidence, Geomagnetic and Fault are used. Finally Data are combined together by using fuzzy logic and binary index overlay methods to effect of various factors in potential geothermal are measured together. The results of potential geothermal zonation indicate L.S.T factor are most important in geothermal zonation in this area. The results of potential geothermal zonation based on fuzzy logic and binary index overlay methods, respectively 10.34, 17.3, 24.9, 16.7 and 30.6% of the area are at very high risk class, high, medium, low and very low. Therefore, it was recognized that the South, Southwest, Northwest and East parts of the study area have more potential for detailed exploration in the future, and it was proved that these combination methods can be very practical in geothermal resource studies.