The　effects　of　biosurfactant　rhamnolipid　and　chemical　surfactant　Tween　80　on　ethanol　production　from　waste　rice　straw　by　simultaneous　saccharification　and　fermentation　(SSF)　were　investigated.　The　results　showed　that　ethanol　yield　was　increased　to　different　extents　by　the　two　surfactants　at　the　optimal　condition.　The　maximum　enhancements　were　obtained　at　the　reaction　time　of　72　hours,　at　which　time　ethanol　yields　were　84.8%　and　91.7%　with　presence　of　1CMC　(Critical　Micelle　Concentration)　of　rhamnolipid　and　Tween　80,　and　the　ethanol　yields　were　12.2%　and　21.3%　higher　than　the　control,　respectively.　The　experiment　proved　that　rhamnolipid　and　Tween　80　could　improve　the　complex　system　of　SSF.　Ethanol　concentration　was　also　increased　remarkably　with　two　surfactants.　The　stimulatory　effects　on　ethanol　yield　of　Tween　80　were　superior　to　that　of　rhamnolipid.　Tween　80　did　not　inhibit　cell　growth　in　fermentation　processes　and　probably　improved　the　utilization　of　reducing　sugar　by　yeast.　For　its　complexity　of　reactive　system,　many　influencing　factors,　more　research　is　needed　to　investigate　effects　of　surfactants　on　yeast.　©　2011　IEEE.