The invention relates to a DC fault arc detection and protection device, and belongs to the field of electrical engineering. The device comprises a high-frequency current transformer, a Hall current sensor, an amplifier, a bandpass filter, a high-precision ADC, a digital signal processor (DSP) and an IGBT circuit breaker, an output terminal of the high-frequency current transformer is connected with an input terminal of the amplifier, an output terminal of the amplifier is connected with an input terminal of the bandpass filter, an output terminal of the bandpass filter is connected with an input terminal of an AD sampling circuit, an output terminal of the AD sampling circuit is connected with an input terminal of the digital signal processor, and an output terminal of the digital signalprocessor (DSP) is connected with the IGBT circuit breaker. A current signal obtains a high-frequency current component through coupling via the high-frequency current transformer, the signal is amplified by 10 times through the amplifier and then passes through the bandpass filter, the ADC samples the signal and transmits the signal to the DSP for algorithm processing, the Hall current sensor transmits a detected DC current value to the DSP for dynamic threshold calculation, and an arc is extinguished through the circuit breaker after detection of arc generation so that protection is realized.