An arc fault detection device, comprising: a first sensor, which is connectable in series in an electric power system line and which is configured to collect circuit signals of a first frequency range in the electric power system line; a second sensor, which is connectable in series in the electric power system line and which is configured to collect circuit signals of a second frequency range in the electric power system line, wherein frequencies in the first frequency range are lower than those of the circuit signals of the second frequency range; a first envelope waveform generator, which is connected to the first sensor, and receives the circuit signals of the first frequency range that are collected by the first sensor and generates a first envelope waveform; a second envelope waveform generator, which is connected to the second sensor, and receives the circuit signals of the second frequency range that are collected by the second sensor and generates a second envelope waveform; and an analysis device, with input ends thereof being connected to the first envelope waveform generator and the second envelope waveform generator and an output end of the analysis device configured to be coupled to a switch device on the electric power system line, and the analysis device receiving the first envelope waveform and the second envelope waveform, and determining, based on the first envelope waveform and the second envelope waveform, whether current in the electric power system line generates an arc fault signal, wherein when an arc signal is generated in the electric power system line, the analysis device drives the switch device to perform tripping, characterised in that the analysis device is a neural network analysis device, which executes a neural network based on an arc fault detection algorithm. a first sensor, which is connectable in series in an electric power system line and which is configured to collect circuit signals of a first frequency range in the electric power system line; a second sensor, which is connectable in series in the electric power system line and which is configured to collect circuit signals of a second frequency range in the electric power system line, wherein frequencies in the first frequency range are lower than those of the circuit signals of the second frequency range; a first envelope waveform generator, which is connected to the first sensor, and receives the circuit signals of the first frequency range that are collected by the first sensor and generates a first envelope waveform; a second envelope waveform generator, which is connected to the second sensor, and receives the circuit signals of the second frequency range that are collected by the second sensor and generates a second envelope waveform; and an analysis device, with input ends thereof being connected to the first envelope waveform generator and the second envelope waveform generator and an output end of the analysis device configured to be coupled to a switch device on the electric power system line, and the analysis device receiving the first envelope waveform and the second envelope waveform, and determining, based on the first envelope waveform and the second envelope waveform, whether current in the electric power system line generates an arc fault signal, wherein when an arc signal is generated in the electric power system line, the analysis device drives the switch device to perform tripping, characterised in that the analysis device is a neural network analysis device, which executes a neural network based on an arc fault detection algorithm.