An injector driver and an operating method thereof are provided in which a driving semiconductor directly controls a brake signal when a brake error occurs in driving an injector, to thus secure a safety function. The injector driver a driving semiconductor configured to transmit an interrupt signal for acknowledging whether a brake signal has been received to a micro-control unit (MCU) when a brake signal is applied. In addition, the driving semiconductor receives a brake signal recognition acknowledgement response signal from the MCU and detects whether the MCU has an error based on the brake signal recognition acknowledgement response signal reception result Further, the driving semiconductor operates an injector driving signal when the response signal is not received from the MCU for a predetermined period of time.