The invention relates to a double-exciting solenoid type abrasion particle online detecting method with a filter. The pressure/flow pulsation of hydraulic oil is attenuated through a filter, and the full-band hydraulic system pressure pulsation filter is adopted. Ferromagnetic particles are separated from non-ferromagnetic particles through the technologies of mechanical centrifugation, magnetizing adsorption, electrifying adsorption and the like, and the situation that a detecting result is influenced by interference between the two kinds of particles is prevented. The particle diameters are increased and the morphologies of the particles are changed through particle polymerization and rotating magnetic field shaping so that the sensitivity of detection can be improved. The structure of a solenoid coil is improved and the homogeneity of the magnetic induction intensity in a solenoid in the axis direction of the solenoid is adjusted to reduce the detection error. Two exciting coils are oppositely connected in series, magnetic fields at the positions of induction coils located in the centers of the two exciting coils cancel each other out, a zero magnetic field is formed, it is guaranteed that a very large magnetic flux change rate can be acquired when the magnetic flux changes slightly, the detection sensitivity is improved, and requirements of follow-up signals for treatment circuits are lowered.