The effects of several collectors and their dosage on pure ilmenorutile at different pH values were studied and the collecting strength of several representative collectors was investigated. The experimental results indicate that diphosphonic acid is a good collector for ilmenorutile and the recovery of ilmenorutile ranges from 90.87% to 91.70% when the pulp pH value is 2.0-4.0 and the dosage is 75mg/L. The sequence of collecting ability for several collectors is as follows:diphosphonic acid > TF279 > cyclic alkyl hydroximic acid > benzyl arsenic acid > salicylic hydroximic acid > alkyl hydroximic acid. Meanwhile, IAS (infrared absorption spectrum) and XPS (X-ray photoelectron spectroscopy) were used to detect and analyze the action mechanism of diphosphonic acid on ilmenorutile. IAS results showed that the characteristic absorption peak relating to P=O as well as P-O vibration occurred between wave numeber 1 140 and 1 032cm^-1, and diphosphonic acid had adsorbed on the surface of ilmenorutile. XPS results indicated that the binding energy of P2P peak of ilmenorutile had changed 0.45 eV after treated by diphosphonic acid. This proves that the adsorption is mainly chemical adsorption.