UASB anaerobic digestion is one of the most suitable used to treat waste especially grey water. UASB (Up-flow Anaerobic Sludge Blanket) is one of a kind anaerobic wastewater treatment that operated continuously, sewage flowed vertically in the UASB fermenter from the bottom toward the top pass Sludge Blanket which there is microbial decomposition of waste in it. Domestic waste has a huge contribution to the contamination ofwater. Domestic waste consists of black water and grey water, but grey water is the most polluting water and there is a few efforts to manage it recently. This studyusingartificialwastethat has beenadapted tothe originalgrey waterwith thehighestrangein the Gabahan Village, andBSB Neighborhoodis thelowestconcentration rangewhichwill beanalyzed then byvarying theinfluent flow and concentration so that the qualityof theinfluentandeffluentof eachBOD5andCOD parameter will be known. There are 5 variations of concentration and flow for 25 reactors which extracted the most optimum removal efficiency within designated parameters BOD5 and COD. The results showedthat by varying the influentconcentration, the range of valuesof CODremoval efficiencyreached40-77% and 38-75% ofBOD5allowance. Themiddle concentration being the most optimum in the BOD5 allowance with percentage 0f 75% and COD by 77% andthe most optimum flow variations on0,405L/ hourwiththe longestHRTto 12Hours. Results of the research showedthat the higher flow will decrease the removal efficiency of BOD5and COD.