Abstract: In order to investigate the loss mechanism of fine-grained ilmenite during magnetic separation process of the titanium beneficiation plant in Panxi region, four sizes fractions of ilmenite and titanaugite minerals were prepared.It was shown that with the increase of applied magnetic field strength, the magnetic susceptibilities of each ilmenite fractions converged from 1.40×10^-6 m³/kg to1.50×10^-6 m³/kg, while those of titanaugite converged from 0.32×10^-6 m³/kg to 0.43×10^-6 m³/kg.Results of magnetic separation experiments of mixed ores indicated that the content of ilmenite in concentrate mainly were influenced by the size of titanaugite and its recovery was predominantly affected by the size of itself.The required applied magnetic force of ultrafine ilmenite increased substantially compared to that of coarse fractions, and it could not offer by normal high intensity magnetic separator, which resulted in the loss of ultrafine ilmenite.Therefore, to collect the coarse and the fine of ilmenite in corresponding magnetic separators which can offer customized magnetic field forces, or to enlarge ilmenite clusters, can beneficiate the fine-grained ilmenite efficiently.Moreover, to avoid overgrinding and slimming ilmenite in iron beneficiation process is the basic way to increase the recovery of ilmenite.