[en] In the current study we proposed a new band ratio combination by using Landsat Enhanced Thematic Mapper (ETM +) image. The new proposed band ratio has been tested for its effectiveness in four regions in the study area. This proposed band ratio (5/3, 3/1, 7/5 in RGB respectively) with the help of supervised classification technique were succeeded in discrimination of different types of rock units. The results revealed that by using the proposed band ratio it was so effective to discriminate different granitic phases (Kadabora region); serpentinites from metasediments and sheared granites (EI Mayite region); mollase type Hammamat sediments from meta volcanics and metasediments (Wadi EI-Miyah region); and serpentinites from meta volcanics (EI-Baramiya region). The results demonstrate the accuracy and suitability of using this band ratio as a powerful tool in lithological mapping and the data was verified by field investigation and previous studies