With the rapid development of industrial technology, large and complex machinery equipment are used for a large number of long periods of time in production, so it is inevitable that there will be wear of parts, and the debris generated by wear will be doped in the lubricating oil, so the detection of debris in the oil is particularly important for the condition monitoring of the equipment. Based on the principle of electromagnetic induction, the use of alternating current drive avoids the heating problem of DC drive sensor. Maxwell software is used to model the internal magnetic field distribution of the oil debris sensor, analyze the influence of various structural parameters on the output signal of the sensor, simulate the core size of the strengthened magnetic field and analyze the magnetic field change inside the sensor, also design the corresponding signal processing circuit and the excitation signal generation circuit. The sensor finally realizes the detection of 200 μm ferromagnetic abrasive grains and 500 μm non-ferromagnetic abrasive grains in the 8 mm flow channel.