A　novel　magnetooptic　current　sensor　(MOCS)　based　on　the　S-waveplate　is　proposed,　which　enables　the　linear　demodulation　of　the　Faraday　rotation　angle,　thereby　addressing　issues　of　nonlinear　demodulation　and　optical　power　dependency.　The　S-waveplate　MOCS　converts　the　Faraday　rotation　angle　into　the　displacement　of　bright　and　dark　interference　fringe　spots,　and　the　displacement　is　then　determined　to　directly　measure　the　Faraday　rotation　angle.　The　S-waveplate　is　a　continuous　device　that　can　achieve　100%　polarization　conversion,　and　a　high-resolution　image　acquisition　is　designed　to　precisely　locate　the　spot,　so　the　S-waveplate　MOCS　shows　a　high　current　sensitivity.　The　experimental　results　demonstrate　that　the　proposed　MOCS　achieves　a　0.2　class　accuracy　with　the　current　sensitivity　of　0.093　A/px　and　exhibits　strong　robustness　and　reliability　in　the　temperature　test.　©　1963-2012　IEEE.