Abstract: Effective magnetic field measurement is essential for ensuring the reliability of magnetic field applications. The demand for magnetic field monitoring on large-curvature surfaces and in high electromagnetic interference environments in aerospace, energy equipment, and complex civil structures is increasing. However, existing magnetic field sensors still exhibit limitations in flexibility, array deployment, and wireless transmission. This study proposes a novel wireless-flexible-array magnetic field sensor based on the magneto-thermal effect of magnetic nanoparticles. Configuration design and material optimization of the sensors are performed. A fabrication process is developed to enable flexibility, wireless transmission, and arrayed integration. The interfacial mechanical properties of the sensors are investigated by employing 90° and 180° peel tests. The effects of substrate type, nanoparticle content, and bending fatigue cycles are considered. The results demonstrate that the temperature rise rate of the array sensing units effectively characterizes the magnitude and spatial distribution of magnetic field. The sensor meanwhile exhibits good interfacial bonding performance. No interfacial delamination is observed under different substrates, nanoparticle contents, or bending fatigue loads. These results indicate stable interfacial behavior and long-term service capability of the sensor. The proposed sensor and the mechanical test results provide experimental support for the engineering application of flexible array magnetic field sensors.