The invention discloses a magneto-optical current sensor and a manufacturing method thereof. A modularized device structure is adopted. The magneto-optical current sensor comprises an optical fiber input module, an optical fiber input correction module, a magneto-optical crystal module, an optical fiber output module and an optical fiber output correction module which are sequentially arranged along the optical path direction, wherein the optical fiber input correction module is connected with a polarizing beam splitter of the optical fiber input module and is outputted to the magneto-opticalcrystal module together with the optical fiber input module. The output of the magneto-optical crystal module is connected with a polarizing beam splitter of the optical fiber output module. The optical fiber output correction module is connected with the polarizing beam splitter of the optical fiber output module. The invention carries out dual correction on the optical fiber input and optical fiber output through the modularizing design, solves the noise caused by optical system shaking or temperature shifting and the like, and adopts the buffer layer to strengthen the adhesion force between the permanent magnetic film and the substrate, thereby enhancing the magnetic property of the permanent magnetic film, increasing the rotary angle of the polarizing light, and improving the measuring precision.