The utility model provides an optic fiber current sensing device based on birefringence real -time measurement, includes: polarization beam splitter, the consecutive inclined to one side laser instrument of guarantor, space polarization controller, optic fibre ware, optical coupler, polarization analysis ware and data collection station, wherein: protecting inclined to one side laser instrument, space polarizer and optic fibre ware and connecting gradually, the output of optic fibre ware links to each other with optical coupler, and optical coupler's output links to each other with polarization analysis ware and polarization beam splitter respectively, and data collection station gathers the polarization state data of polarization analysis ware and the light intensity data of polarization beam splitter respectively to sensing fiber's birefringence size and faraday's angle of deflection are awaited measuring, the utility model relates to a rationally, realize the accurate measurement to faraday's angle of deflection, had the directive significance to reliability and the accuracy that improves fiber optic current sensor practical application.