The main technical bottleneck in the research of on-line inductive wear particles monitoring sensor lies in the contradiction between the sensor sensitivity and channel diameter. The sensor with high sensitivity generally adopts the micro-flow channel structure, leading to a small maximum allowable flow rate, while the sensor with large channel diameter has markedly lower sensitivity. To satisfy the requirements of online wear condition monitoring of heavy machinery, the sensitivity improvement method of large aperture inductive abrasive particle sensor is studied. It is proposed to make the sensor work in full resonance state, in which the excitation coil works in the parallel resonance state and the induction coil works in the series resonance state so as to jointly enhance the sensor output induced electromotive force caused by the wear particles. For the detection mechanism, a perturbation model of magnetic field caused by wear debris in the alternating magnetic field is established, which considers the eddy current effect of particles in alternating magnetic field and improves the practicability of the model. The experimental results show that the resonance mechanism largely increases the sensitivity of the sensor, which can successfully detect up to 75 μm ferromagnetic particles and 220 μm non-ferromagnetic particles, and satisfy the online monitoring requirements of initial abnormal wear stage of the heavy machineries.