The wire rod electrolysis is an extraction approach of inclusions in wire rod based on non-aqueous solution electrolysis, which can extract large-size inclusions (>20 µm) from Φ5.5 mm wire rod even about Φ0.22 mm cord wire. Analysis and study on large-size inclusions in tire cord steel from domestic and overseas steel plants were carried out by wire rod electrolysis, the study shows that the sizes of inclusions in wire rod of tire cord steel are far larger than those observed by metallographic microscope or scanning electron microscopy. Eighty percent large-size inclusions in wire rod come from the involvement of reaction products of mold fluxes or refractories. Further study according to electrolysis of wire rod and cord wire presents that reaction products containing K and Na of mold fluxes and refractories are brittle and easy to break into more small inclusions. Wire broken during drawing process is mainly caused by large-size and high-hardness Al2O3 inclusions, inclusions containing high content MgO from reaction products of mold fluxes and refractories, and Ti(CN) inclusions.