A　novel　scheme　of　surface　acoustic　wave　(SAW)　SO2　gas　sensor　based　on　the　carbon　nanotube-polyanilin　films　is　proposed.　The　carbon　nanotube-polyanilin　films　are　fabricated　on　the　measure　acoustic　track　of　surface　acoustic　wave　device　on　128°YX-LiNbO3　crystals.　Because　the　dual　track　receiving　structure　is　incorporated　into　the　sensor,　the　measurement　errors　caused　by　the　environmental　disturbance　are　eliminated,　and　the　reliability　and　accuracy　are　further　improved.　The　carbon　nanotube-polyanilin　films　prepared　by　the　in-situ　polymerization　can　increase　the　absorb　area　of　SO2　gas,　and　sensor　sensitivity　is　improved.　Experimental　results　confirm　that　the　surface　acoustic　wave　SO2　gas　sensor　based　on　carbon　nanotube-polyanilin　films　is　endowed　to　excellent　response　performance.　When　SO2　gas　injected　is　1　×　10-6,　the　sensitivity　reaches　to　8.3　kHz　in　measurement　range,　about　1.8　kHz　higher　than　the　sensor　with　only　polyanilin　films.　Furthermore,　the　sensor　has　better　linearity　sensitivity　compared　with　the　sensor　with　only　polyanilin　films.