The aim of the study is to determine the changes of steppe flora at upper Mesopotamia according to seasons. Depending on the blooming phenophase of the plants picked from the research area, the seasonal conditions of the pasture flora and vegatation have been examined. Replacements of plant associations are also detatinined according to the seasons. According to the results, the spring and summer flora seemed to have the highest densities (386 and 207 taxa, respectively). There are 102 taxa in the autumn flora and only 42 taxa in the winter flora. At the results of soil analysis, salinisation has been determined in some areas. Halophytic plants and associations are expressed. The region climatic data are also discussed. The change of flora and vegetation is described according to climate. Additionally, the productivitiy of pastures and threat factors are also discussed. Excessive grazing causes to transforming of primary steppe to secondary and than semi-desert to desert vegetation.