The utility model relates to an optical current transformer, including public light source, based on linearly polarized light measuring principle's a measuring unit with based on circularly polarizedlight measuring principle's the 2nd measuring unit, a measuring unit includes a transmission fiber and detection module, and the 2nd measuring unit includes the 2nd transmission fiber and measuring principle 1, and detection module is connected through a transmission fiber to public light source, connects measuring principle 1 through the 2nd transmission fiber. Include two kinds of measuring principle's measuring unit among this optical current transformer, for the photoelectricity current transformer based on single measuring principle, this optical current transformer's interference immunity has obtained promoting very bigly, has realized two kinds of measuring principle's complementation, and consequently, the reliability of this mutual -inductor is stronger.