The present invention relates to a transformer relay and a battery voltage measurement system using the same and the transformer relay includes: a transformer unit transforming voltage of a voltage measurement signal according to a wiring ratio of a first wiring and a second wiring; and a relay unit transferring voltage of a battery while an operation state is changed to an On state when the transformed voltage of the voltage measurement signal is input and the battery voltage measurement system using the transformer relay, includes: the transformer unit; and a measurement unit measuring a battery voltage value by receiving the voltage of the battery from the relay unit.
