Propene　(C3H6)/propane　(C3H8)　separation　is　an　important　but　challenging　industrial　task.　Adsorptive　separation　using　porous　materials　tends　to　be　an　energy-and　cost-effective　strategy.　In　this　work,　a　flexible　porous　MOF　named　NJU-Bai8　is　demonstrated　to　be　a　promising　adsorbent　for　the　effective　separation　of　C3H6　and　C3H8　in　a　wide　temperature　range　from　298　to　348　K　due　to　its　flexible　microporous　structure,　which　provides　unique　guest　responsive　molecule　accommodation.　Adsorption　isotherms,　ideal　adsorbed　solution　theory　(IAST)　prediction　of　separation　ability,　and　transient　breakthrough　on　both　simulation　and　experiment　were　performed　to　evaluate　its　separation　selectivity　and　cycling　experiments　were　carried　out　to　explore　its　structural　stability.　It　was　found　that　the　C3H6/C3H8　uptake　ratio　and　IAST　selectivity　of　NJU-Bai8　is　43.2　and　4.6　at　298　K　and　20　kPa,　respectively.　The　breakthrough　time　interval　for　C3H6　and　C3H8　is　over　10　min　for　a　C3H6/C3H8/He　(20%/20%/60%)　mixture　under　ambient　conditions,　and　this　separation　ability　can　maintain　more　than　10　cycles.　Detailed　analysis　reveals　that　a　guest-dependent　pressure　induced　gate-opening　effect　in　the　flexible　framework　of　this