Abstract:Through collecting the measured geostress data from about 400 drillings up to now in China mainland,450 groups of data with less local influence are selected. The trend of the vertical stress,the maximum and the minimum horizontal principal stresses with depth are established;and the results are compared with the world-wide corresponding regression analysis results. The dispersed point charts of ratios of the maximum and the minimum horizontal principal stresses varying with depth in China are established;and the change rules of the ratios with the depth are studied. As the difference between the maximum and the minimum horizontal principal stresses is great,especially in shallow positions,the ratios of the maximum horizontal stresses to the vertical stresses reflect the horizontal tectonic stress better than the average horizontal stress. The geostress statistic analysis method of Hoek and Brown,which uses the ratio of the average horizontal stress to the vertical stress to study the change rules of geostress with depth,is improved. The dispersed point charts of the ratio of the maximum horizontal stress to the vertical stress and the ratio of the minimum horizontal stress to the vertical stress with depth in China are established;and the corresponding regression analysis is also done. The distribution rules of geostress in China mainland is systematically summarized;some statistic forms are used firstly;and the research results can provide references to the study of macroscopic distribution characteristics of geostress in China mainland and for engineering constructions of related industries.