Abstract: The study area lies in the northern part of Iraq in the western part of Nainawa governorate. It is surrounded by Tigris River to the east, Mashuradagh anticline to the north, Sinjar anticline and Baaj area to the west and Al- Gayara region to the south, The study area locates within the foothill subzone including Mosul block consisting of secondary blocks which was suggested by a stratigraphic correlation based on deep oil exploration wells. The Bouguer gravity map covered the study area reflects a gravity high which its centre locates near Atshan anticlinal structure. The previous gravity high extends over many anticlinal structured surfaces Allan, Shaikh -Ibrahim, Sasan, Ishkaft, Gusair, Ain-Zalah, Butma, Rafan, Atshan, Nwaigit, Qlaian, Adayia and Najma. Twenty-three gravity traverses were chosen. (T1-T8) with NW-SE direction and the others (T10-T24) with NE-SW. The present study conducted simulation of gravity data with different computer techniques taken in to consideration the previous studies. The calibrated gravity field was chosen visually and upward continually avoiding both the personal bias and the pure mathematic. Mosul block reflects a huge mass of 120 Km length and 60 Km width which is divided into a southern block with Zagrosian trend and a northern Taurosian trend by a strike-slip fault might explaining why the anticlines changing their axes orientations from NW-SE to the southern one with E-W on the northern. The gavity anomally of Mosul block reflects density vaiation between basement rocks and the sedimentary cover. On the other hand, the study explained subsidiary block faults surrounding and within Mosul block which extends in role to deep depths. This conclusions leads to the large importance of the study area due to presence of hydrocarbon resources in sedimentary basins as a result of tectonic activities during the geological eras.