A steam ejector is designed for converting energyin a form of pressure into kinetic energy in a form ofsupersonic velocity for entrainment the low pressuresteam and mixed them together. By flowing pass throughthe nozzle that is changed in each cross section area.The objectives of this research are studying to findthe parameter that concern with designing steam ejectorand able to recovery the low pressure steam and bringit into process again for saving energy. Test will be done by using pressure ratioP(,01)/P(,02) at 4 locations of primary nozzle with 4Mach numbers, these are 1.7, 1.9, 2.2 and 2.4 bycompare with variation of entrainment ratio for knowingthe available efficiency in each case. If the staticpressure at exit nozzle match to secondary pressure,can give the higher efficiency of system that canneglect the effect from shock wave that maybe happen.And also optimize length of distance from primarynozzle to mixing throat will give the higherefficiency. The pressure that is chosen will relatewith Mach No. at exit primary nozzle for matchingpressure. By this research hold that the flow isadiabatic flow in all mixing length. Model loss of steam ejector can predict theavailable efficiency and give idea to develop steamejector efficiency is higher. Adjustment the value ofcl is appropriate with any model will can predict theresult of loss is more accuracy.