The output accuracy and stability of the optical fiber voltage sensor can be seriously affected under the disturbance of external ambient temperature.Therefore,this paper proposes a sensor head optimization method using polarization maintaining photonic crystal fiber (PM-PCF) as the sensing fiber to suppress the system′s nonreciprocal error under temperature disturbance.Consideration of the fusion loss,transmission loss between the traditional panda polarization maintaining fiber (panda-PMF) pigtail and PM-PCF,and the fiber fabrication problem under the existing technological conditions,a PM-PCF with the fusion loss as low as 0.14 dB between it and the traditional panda-PMF is optimized.The birefringent temperature dependence characteristics of the two kinds of polarization maintaining fibers are compared and analyzed.And the thermal system error output model of the fiber optic voltage sensor (FOVS) is established.Then,the feasibility of PM-PCF in solving the thermal nonreciprocity problem of reflective inverse piezoelectric FOVS is analyzed and verified.The results show that the thermal nonreciprocity error of the FOVS optimized by PM-PCF is about 10-2 of the traditional PCF voltage sensor.It has significant advantages in improving the output accuracy and stability of the system.At the same time,this low-loss optimization method has important value in fiber sensing and communication application area.