Suction　injection　cooling　can　be　usually　used　in　scroll　refrigeration　compressor　which　works　under　the　high　speed　or　high　pressure　ratio　condition,　when　the　atmosphere　is　severe.　In　the　present　paper,　the　suction　injection　process　is　simulated　with　isobaric　adiabatic　mixing　model,　which　has　been　employed　by　many　researchers;　and　the　performance　of　the　scroll　compressor　with　suction　injection　cooling　was　investigated　experimentally.　The　test　rig　was　established,　and　the　scroll　compressor　with　suction　injection　cooling　was　measured　when　the　pressure　ratio　rose　from　3.4　to　4.5,　and　the　injection　volume　flow　rate　rose　from　0　to　0.085　m(3).h(-1).　The　results　indicate　that　the　discharge　temperature　decreases　remarkably　with　the　injection　volume　flow　rate.　Also,　the　COP　(Coefficient　of　Performance)　decrease　with　the　injection　volume　flow　rate.　When　the　injection　mass　ratio　is　lower　than　20%,　the　decrease　of　COP　is　acceptable,　at　different　pressure　ratio.　At　high　pressure　ratio,　the　COP　could　keep　unchanged　when　the　injection　mass　ratio　is　lower　than　10%.　Hence,　the　effect　of　suction　injection　cooling　is　better　at　the　high　pressure　ratio　and　low　injection　volume　flow　rate.　The　ideal　simulation　results　agree　well　with　the　experimental　ones　at　low　injection　volume　flow　rate,　but　deviate　from　that　at　high　injection　volume　flow　rate.　This　is　because　that　the　gas-liquid　separation　happened　at　high　injection　ratio,　and　the　isobaric　adiabatic　mixing　model　could　not　predict　the　process　practically.　Therefore,　a　new　model　will　be　developed　to　describe　the　process　accurately.