Organic　Rankine　cycle　(ORC)　plays　an　important　role　in　addressing　the　issue　of　energy　shortage　and　climate　change.　The　condenser　should　release　heat　to　the　environment.　Due　to　the　seasonal　and　daily　variations　of　ambient　conditions,　the　condensation　temperature,　power　consumption　of　the　cooling　system,　the　operation　conditions　of　the　working　medium　pump　and　expander　would　suffer　drastic　changes　in　different　condensing　ambient　conditions.　Therefore,　the　main　aim　of　this　study　is　to　investigate　the　cross-seasonal　performance　of　the　organic　Rankine　cycle　under　variable　condensation　conditions.　Simultaneously,　the　single　screw　expander　with　quasi　two-stage　expansion　was　used　to　improve　the　performance　of　ORC　in　different　condensing　ambient　con-ditions.　A　model　was　developed　to　depict　the　variations　of　operation　parameters　of　ORC　system.　The　results　show　that　the　performance　of　ORC　was　adversely　correlated　with　the　wet-bulb　temperature　throughout　the　year.　The　net　power　and　net　efficiency　can　be　reached　at　8.04　kW　and　11.31　%　when　the　wet-bulb　temperature　is　1.1　celcius,　respectively.　Additionally,　the　variation　in　cooling　water　flow　rate　has　little　effect　on　the　volumetric　expansion　process　of　the　new　single　screw　expander,　but　has　a　significant　influence　on　the　velocity　expansion　process,　which　increases　by　nearly　56.4　%.　Meanwhile,　decreasing　the　pipeline　impedance　coefficients　of　cooling　system　can　optimize　ORC　system　performance　effectively.　It　was　also　discovered　that　the　isentropic　efficiency　of　single　screw　expander　decreases　by　only　8.68　percentage　points　during　the　expansion　ratio　increase　from　3.31　to　11.54.