There　are　few　systematic　studies　to　investigate　the　inherent　reason　behind　the　evolution　law　of　ejector　performance,　only　some　simple　qualitative　or　roundabout　analysis.　In　this　paper,　a　double-choking　theory　is　proposed　to　provide　an　in-depth　explanation　of　the　evolution　laws　of　ejector　performance.　The　systematic　investigation　and　quantitative　analysis　focus　on　the　influences　of　various　operational　and　geometrical　parameters　on　the　ejector　choking　flows.　Key　results　revealed　that　the　flow　area　of　the　primary　jet　flow　at　the　choking　cross-section　A(py)　almost　linearly　increases　with　higher　primary　flow　pressure　p(p0),　while　the　entrainment　choking　area　A(ey)　declines　instead,　and　thus　the　entrainment　ratio　epsilon　decreases.　The　mixing　pressure　p(y)　significantly　increases　with　entrainment　pressure　p(e0),　and　A(py)　partly　reduces.　Consequently,　A(ey)　becomes　larger　and　epsilon　is　accordingly　with　an　over-double　increase.　A(py)　undergoes　a　continuous　decrease　when　the　area　ratio　of　primary　nozzle　lambda(t)　increases,　and　thus　e　rises　consistently　although　A(ey1)　eventually　experiences　a　slight　decrease.　However,　the　choking　state　of　the　entrained　flow　would　discontinue　as　lambda(t)　exceeds　its　critical　value　lambda(tc).　Additionally,　A(ey)　increases　substantially　when　the　area　ratio　of　the　constant-area　section　lambda(3)　enlarges,　while　A(py)　and　p(y)　always　remain　unchanged.　Accordingly,　epsilon　follows　the　same　increasing　trajectory　as　A(ey).　These　impactful　results　could　serve　as　an　essential　guide　for　optimizing　the　ejector　design,　and　also　ensure　a　clearer　perspective　to　understand　the　fundamental　link　between　the　ejectors　entrainment　performance　and　choking　flow.