We　propose　a　high-sensitivity　temperature　sensor　with　a　long-period　fiber　grating　(　LPFG)　using　Mach-Zehnder　and　Sagnac　interference　of　the　optical　path.　The　LPFG　sensor　achieved　a　good　repeatability　and　stability　of　temperature　response　with　a　sensitivity　of　0.083nm/degrees　C　in　the　range　of　40　degrees　C-120　degrees　C　Comparing　to　the　traditional　fiber　Bragg　grating　(FBG)　sensor,　the　LPFG　sensor　shows　10　times　higher　temperature　sensitivity　than　that　of　the　FBG,　so　the　problem　of　low　sensitivity　of　FBG　is　solved.　Otherwise,　Mach-Zehnder　and　Sagnac　interference　of　the　optical　path　have　the　advantage　of　simple　structure　and　good　practicability　which　can　replace　the　complex　optical　path　in　the　special　environment.