The historical centers in Arab cities play a vital role in confirming their cultural and heritage dimension that are reflected of social, cultural, economic and environment in the urban fabric. Many contemporary changes have taken place made a great impact on the historical cities, and many of their heritage buildings have been changed in a way desecrated their identity rather than rehabilitated and reused them in a method that keeps up with the social development that meets with the needs of their inhabitants and the requirements of the time. Mosul is one of the ancient cities, Throughualy the history, has left us a cultural and urban heritage that carried a great importance and a high value represented by many of historical and heritage buildings. Now and because of, the recent war that has a great harmed on the city by its urban organization , especially in its ancient area, and In order to preserve on this heritage from extinction, neglect and misuse, this research aims to Determination the valuables of re-use for historical buildings through reviewing the potential of the re-use with its capabilities, criterias, characteristics and the considerations that should be adopted on the process of conservation and re-use. Finely, The objectives should meet with the need and the function accordance to the requirements of the area and the age, and the old building should operation, preservation, economically, socially, and sustainabily through generations.; preservation