The main focus of this study was to investigate and evaluate the Performance of Four Regional Climate Models irrespective of their capability in simulating mean precipitation and Temperature. In this fact and concern, the evaluation of those climate models was basically on how they simulate mean annual climatology, annual cycle and interannual variability of precipitation, maximum and minimum temperature over the entire catchment. All observed data used for the baseline period of 1980-2006 was obtained from Ethiopian National Meteorological Agency and RCM data was extracted from CORDEX-Africa-44 using grid points. RCM shows significant bias and almost all of them simulate those climate variables' at different levels. In the analysis of the annual cycle of precipitation during the summer season, all RCM was underestimated. However, RACMO22T and RCA4 show better adjustment at the simulation of both precipitation and Temperatures despite their significant bias. The bias was deliberately associated with the higher error in simulating maximum and minimum temperature at the highest topography found at sebeta and Addis Ababa catchments. The inter-annual variability of precipitations and temperature was shown as great evidence where the region is under the impact of climate change specifically when the trend of annual projected temperature shown incremental modality. As far as concern the mean climatology analysis by statistical parameters, almost all models perform nearly equal excluding the seasonal point of view in which RCMs performed quite differently during season analysis. In all aspects and evidence by statistically evaluated output realize that RACMO22T and RCA4 were better performed at upper awash catchments although some of their bias and uncertainty were available. Generally, the performance of Regional climate models was different at different catchments along with the specified locations and topographies. Furthermore, the seasonal analysis over Akaki catchment indicates that climate models were more capable of simulating wet season than dry.