The invention discloses a low-voltage line voltage protector. The protector is characterized by comprising a voltage signal acquisition analyzer and a circuit breaking protector. The voltage signal acquisition analyzer comprises a voltage single detection module and a carrier signal generator and is mounted at the tail end of the low-voltage line directly through three-phase four lines. The circuit breaking protector comprises a carrier signal receiving module and a breaker and is mounted on a power bus at the head end of the low-voltage line. According to the protector, voltage monitoring is performed on the low-voltage line, the voltage monitoring alarm value can be set, and when the voltage single detection module monitors the voltage of the low-voltage line is too high or too low to exceed the alarm value, the carrier signal generator sends signals to be transmitted to the head end of the low-voltage line through a distribution line, the carrier signal receiving module receives the signals to control the breaker to cut off a power supply of the low-voltage line rapidly, accordingly, user equipment of all users in the whole power distribution station is protected effectively, the investment is small, the protection range is wide, and mounting and running maintenance are facilitated.