A　strain　sensor　based　on　high-birefringence　(HB)　fiber　loop　mirror　was　theoretically　and　experimentally　investigated.　When　the　HB　fiber　is　applied　to　axial　strain,　the　transmission　spectrum　of　the　high-birefringence　fiber　loop　mirror　shifts.　The　relationship　between　the　shift　of　resonant　wavelength　and　the　strain　was　derived.　The　experimental　result　which　is　in　good　accordance　with　the　theory,　shows　that　the　resonant　wavelength　shift　is　0.0318　nm/μΕ,　which　is　32　times　higher　than　that　of　fiber　Bragg　gratings.　The　linear　regression　is　0.9994.　The　strain　sensor　has　the　advantages　of　high　sensitivity,　compact　configuration　and　convenient　use.