A thin film standardless analysis method, based on the Cliff-Loriner factor k, has been used to do quantitative x-ray analysis of asbestos fibers in the TEM. The results of the analysis of four minerals at 120 keV were close to the theoretical value. The ionization cross section Q has been revised experimentally to improve the analysis of asbestos.The Cliff-Lorimer factor has been used in TEM thin film analysis since 1975. The factor kAB is used in the following equation:CA/CB= kABIA/IBwhere CA and CB is the weight percent of the elements A and B. The IA and IB are x-ray intensities corresponding to elements A and B. In this paper the calculated k values2 will be used for standardless quantitative analysis.In the thin film, when the effects of the backscattering electron, x-ray absorption, and secondary fluorescence are not considered, the x-ray intensity iswhere pt is the mass depth AA is the atomic weight of element A, W is the fluorescence yield, L is the ratio of the x-ray lines and T is the detector efficiency.