The structural state of alkali feldspar is a reflecation of its temperature-pressure conditions and, in particular, its cooling rate. Analysis of shifts of diffraction maxima as a fuction of structure and degree of Al-Si order reveals that peaks are most useful for the estimate of Al-Si distribution directly from X-ray data. The 060 and 204 powder-diffraction maxima are in common use in China. For monoclinic alkali feldspars, although the 060 peak is suitable for use, the 204 peak is overlapped by other peaks. Based on a systematic analysis of X-ray powder-diffraction data of alkali feldspar of various series, Hovis proposed a method to determine Tl and T2 site occu-pacies of monoclinic feldspars by use of the 2(9 value of the 113 and 060 peaks from X-ray data. In this paper, the authors utilize the two methods to calculate the structural states of alkali feldspars from the volcanic-intrusive complexes of Xiangshan and Qibaoshan. Comparison of the results reveals that the Al-Si distribution obtained by using the value of the 060 and 113 peaks is more accordant with the geologic case than that obtained by using the 060 and 204 peaks.