The location of tall building in complex region, wind is the powerful factor exerted on tall buildings. This pressure has a direct affected on the drag force. The drag force has a significant impact on the building's surface. All the faces of a tall building's drag force or maximum pressure coefficient have generally been measured through wind tunnel experiments. It's difficult and costly, but it's the best option. Computational Fluid Dynamics (CFD) has been used in this study to determine the external pressure coefficient on the front and back sides of a tall building in the presence of hill interference in complex region. In addition, the current research investigates the behaviour of wind flow around tall buildings at different location of hill first scenario the top of a hill, second scenario the front and third scenario back zones of a hill, and the interactions between tall buildings and the hill itself