Human life has been widely developed throughout earth, especially when mankinds achieve technology. These developments such as landuse changes without consideration to potential and capacity lands including changes in vegetation cover, increasing bare and cultivated lands, deforesting, land degradation, increase desertification, water and life environmental pollution make inappropriate effects and imposible recovery. This is important since land use change have a direct effect on the hydrologic processes through its linkage with the evapotrairation regime and rate and type of ground cover has an enormous impact on the initiation of surface runoff and water and wind erosions. So the research on changing basin hydrologic parameters following landuse changes, is one of the most suitable ways on investigation in quantifying the effects by landuse changes. In this research, we have selected Qale Shahrokh basin (150980.1 ha) for investigation of landuse changes and the effects on hydrologic response. We also produced landuse, CN and runoff coefficient maps in 1354, 1369 and 1381 with using satellite images of MSS 1979, TM 1990 and ETM+ 2002. Then trend of landuse changes and effects on curve number (CN), runoff depth (Q) and runoff coefficient (C) were investigated. The results of the study show that the most landuse changes were between 1354 and 1369 because the rangland with moderate vegetation convert to dry and irrigated farming then rangelands degraded. Most of changes appear to be occured between 1369 and 1381 are directly related to degradation and moderate rangeland converted to dry and irrigated farming. According to this landuse changes, weighted CN and C increased 1.1 and 0.03 during the first study period, 0.24 and 0.02 during the second study period. Also we have an increasing in runoff depth that was 0.25 mm /year between 1354 and 1369, 0.075 mm /year between 1369 and 1381 .
