in the phase quantitative analysis by use fo the x-ray diffraction, the contents of minerals are determined by th.e intensity of diffraction. But many factors have influence over the intensity. The prefrred orientation described in this paper is an important influential factor. The difficulty for phase quantitative analysis of talc qy use of the x-ray diffraction method is the preferred orientation. Because talc occurs in foliated, scaly, or fibrous aggregates. When the samples prepared by usual method, it shows random orientations. The intensites are various. Therefore the phase qu- antitative analysis can not be done. In this paper the "nonpressure method of prepared the samples" is described. It eliminated the preferred orientations completely. Then the satisfactory results are obtained. This method is not only suitable for talc, but is also applicable for all other scaly, slaty, or fibrous mi- nerals of sheet silicates.