The invention provides a low voltage power distribution line line breaking fault identification method and a low voltage power distribution line line breaking fault identification device. Fourier transform of a phase line current signal and a total leakage current signal of a first preset sampling point and Fourier transform of a total leakage current signal, an A phase current signal, a B phase current signal, and a C phase current signal of a second preset sampling point are carried out to acquire the amplitudes and the phase angles of the above mentioned various signals, and based on the amplitude, the phase angles, and the current setting values of the above mentioned various signals, whether a single-phase branch protection criterion and/or a three-phase main branch protection criterion are/is satisfied is determined. By combining the 220V single-phase branch protection criterion and the 380V three-phase main branch protection criterion together, a complete fault detection and protection system is provided for low voltage power distribution system line breaking faults, and faults of a three-phase power distribution wire main branch and faults of a single-phase branch power distribution wire are identified accurately, and therefore whether a protection device is required to cut the faulted line is determined.