In this paper, an all-fiber electric voltage sensor based on high birefringence fiber loop mirror is presented. This voltage sensor is composed of a 3dB coupler and ~8m high birefringence (HiBi) fiber, part of which is affixed to a piezoelectric translator (PZT). When the voltage applied on the PZT changes, the transmission spectrum of this HiBi fiber loop mirror will shift accordingly. As the direct current voltage increases to 75.2V, the phase shift of this HiBi fiber loop mirror is nearly π rad and the transmission peak changes by about half of a period. This voltage sensor has a sensitivity of 0.004nm/V and its linearity reaches 0.99878. Moreover, we have theoretically studied transmission spectrum shift of this HiBi fiber loop mirror when the length and refractive index difference of HiBi fiber are altered.