Abstract: The factors affecting accuracy and tolerance of quantitative analysis on rutile and anatase type TiO₂ using D/max-RC rotating anode type X-ray diffracto-meter are investigated. It is suggested that the reference specimen method should be combined with K-value method to conduct quantitative analysis on rutile and anatase type TiO₂. Under Cu-K_α radiation conditions, the diffraction peak background elimination △2θ is in the range of 0.7~1.2°,scanning rate ≤ 5°/min, the content of rutile or anatase type TiO₂ is above 15% in sample and quantitative tolerance is<5%.