Abstract: The matrix effect on X-ray diffractometric quantitative multiphase analysis was studied through experiments. Influential factors such as K value (I/Ic), diffraction signal intensity, sample particle size for all phases and power of X-ray tube used were emphasized. The results showed that qualitative analysis was the prerequisite of quantitative analysis. Some measures, including using integral intensities, making sample particle size as fine and homogeneous as possible in all phases, using X-ray tube power and suitable scanning speed, were taken and the accuracy of quantitative X-ray diffraction phase phase analysis was remarkably improved.