Steam　ejector　plays　a　critical　role　in　MED-TVC　desalination　system　that　can　achieve　a　good　balance　between　freshwater　production　and　energy　savings.　In　this　study,　a　pressure　regulation　technology　is　proposed　to　optimize　the　entrained　flow　passage　and　thus　improve　the　ejector　performance.　The　theoretical　basis　is　that　there　have　some　existing　low-pressure　potentials　inside　the　ejector　that　can　be　used　to　alleviate　the　high-pressure　effect　and　shock　wave　at　the　mixing　chamber　end.　Then　the　feasibility　verification　and　performance　comparison　of　different　pressure　regulation　schemes　is　implemented　systematically.　Analysis　and　research　mainly　pay　attention　to　the　influences　of　pressure　regulations　on　the　mass　flow　rate,　the　entrainment　ratio　and　internal　flow　field.　The　results　reveal　that　there　is　an　optimum　combination　of　pressure　regulation　schemes,　by　which　a　most　considerable　entrainment　ratio　improvement　could　be　achieved,　as　large　as　11.77%　within　the　simulated　conditions,　and　with　3.94%　even　under　the　design　condition.　More　specifically,　for　the　given　steam　ejector,　TMCE　pressure　regulation　could　be　used　if　the　ejector　operates　under　the　design　condition.　For　the　off-design　conditions,　CMCE　pressure　regulation　is　the　best　choice　if　the　back　pressure　is　larger　than　34　kPa,　otherwise　DMCE　pressure　regulation　should　be　chosen.　(C)　2018　Elsevier　Ltd.　All　rights　reserved.