To address the issues of electromagnetic interference susceptibility and the inability to power conventional electronic angle sensors in high-voltage equipment, a reflective fiber optic angle sensor has been proposed. The sensor operates by rotating a shaft to drive a gear, which in turn actuates a rack mechanism. As the shaft rotates, the reflector on the rack moves horizontally, altering the position of the fiber optic probe. A laser beam is directed towards the reflector, and the intensity of the reflected light, which varies with the rotation angle, is detected through the fiber optic. This intensity is converted into a voltage signal, allowing the determination of the shaft′s rotation angle. The least squares method is used to linearly fit the sensor, establishing a mapping between rotation angle and output voltage. Curve fitting is employed to compensate for nonlinear errors. Experimental results show that after nonlinear compensation, the nonlinear error of the designed angle sensor is reduced from 11.39% to 1.34%, with a measurement error of 0.97.