A wear debris detection sensor used to detect inductance and resistance parameters was presented, which could improve the detection sensitivity of the inductive sensor for nonferromagnetic metal particles. The designed sensor mainly consisted of a ring silicon steel sheet and planar coil. The silicon steel sheet enhanced the magnetic field strength of the detection region, making the magnetization effect and eddy current effect of the metal particles more intense, thereby improving the sensitivity of inductance and resistance detection. Through comparative experiments, it was found that the ring silicon steel sheet does not increase the noise of the inductance and resistance detection signals; and both the inductance and resistance detection capability are stronger for ferromagnetic metal particles. For ferromagnetic metal particles, inductance detection is more effective; for nonferromagnetic metal particles, resistance detection is more effective. By combining the inductance detection and resistance detection results, 55 μm iron particles and 115 μm copper particles can be detected using a planar coil with 20 turns. The wear debris sensor provides technical support for online monitoring of hydraulic oil contaminants.