Abstract: In order to eliminate the influence of preferential orientation of layered silicate minerals on the detection results, matrix flushing method is adopted in X-ray powder diffraction quantitative analysis. Corundum is added as a flushing agent. Pure samples of talc and chlorite are used as references, with a ratio of 1:1 to the corundum. The reference diffraction intensities of corundum, talc and chlorite are measured to calculate the reference strength of talc and chlorite by the reference strength formula. Then the corundum and the definite sample (talc and chlorite mixture) are prepared in the ratio of 1:1 to test the main diffraction peak intensity values of corundum, talc and chlorite. Discarding discrete data, the contents of talc and chlorite are 81.5% and 14.6%, respectively. By EVA semi-quantitative analysis, the contents of talc and chlorite are 92.9% and 5.8%, respectively. The content of chlorite in the definite sample is about 13%, which is close to the definite value of chlorite by the matrix flushing method, but with great difference to that by semi-quantitative analysis. The results show that the analysis of matrix silicate mineral content in the mixture phase by matrix washing is accurate.