The research handles the measuring of functional efficiency in the modern Iraqi city taking Mosul city as a good example of this study, the problem of (lacking resources involved in the field of evaluating the functional efficiency of the modern houses spaces locally) was put on the table of discussion.The theory depended by the research is represented by (the functional efficiency of any building is affected by the space arranging of the involved building) , tow main aims were achieved by the research, the first is represented by (evaluating the functional efficiency of the modern houses spaces locally) the second is concerned with (the possibility of reaching a sample of a space system concerned with the modern spaces houses in such a way that keep it functionally efficient as long as possible).Doing so, it was possible to deal with one of the mathematical analysis methods using a computing program which is (syntax.exe), it provides us with a digital results so precise in analysis, in order to obtain the data, selected samples of modern houses were selected and analyzing them by space syntax theory indicators.Once the theory was selected and the results were obtained, the research made several results by which many questions found their answers, these questions which were mentioned at the beginning of the research are:- 1.How can we collect the functional efficiency with the house space systematizing?2.Is it possible to reach a sample of house in which the space systematizing can be effective in such way with the functional efficiency?3.Is it possible to apply the dependant method in the analyzing on a different other space system of houses that are of different times or even of buildings that are of non-residential functions? Answering these questions, the research realized that the house, as a functional system, containing all of the actions, is still lacking to the succeeding qualifications unless having these functions with certain indicators of the Space arranging that are contributing in some way in evaluating the functional efficiency of that house.