The distribution network is a critical component of the power system. When a fault occurs on an overhead line in the distribution network, the timely and accurate location of the fault point is crucial for prompt line restoration and ensuring reliable power supply. Existing fault location devices exhibit certain limitations when applied to distribution net-works. This study designed and developed a non-invasive sensing device based on a tunneling magnetoresistance (TMR) magnetic field sensor for detecting traveling wave magnetic field signals, applicable for fault location on distribution network overhead lines. The research achieved 12-bit resolution and 5 MHz high-speed sampling of traveling wave magnetic field signals. The modulus maxima method of wavelet transform was employed to achieve accurate identification and pinpointing of traveling wavefronts. A time synchronization algorithm based on the 1PPS (Pulse Per Second) signal from satellite positioning systems and a high-precision oven-controlled crystal oscillator (OCXO) was proposed. The time synchronization error between different sensing devices is less than ±600 ns, and the fault location error is less than ±200 m.