Abstract: Multi-fractal analysis is used to study the structure of rock mass. Attention is paid to the error estimate of main parameters and arithmetic improvement. The four typical outcrops of Silurian system strata close to Baozha landslide and Yangjiashan landslide of Enshi area in western Hubei Province were taken as examples to study the multi-fractal analysis on the structure of rock mass. Clearly, multi-fractal dimension is a direct measurement to the average rock mass quality, and the width of the multi-fractal spectrum can explain the distribution of the rock mass quality within the whole rock mass. Compared with the traditional rock mass quality index, the multi-fractal analysis on the structure of rock mass is better in explaining the global properties of the structure of rock mass. A preliminary method was proposed to assess the rock mass quality based on the results of multi-fractal analysis.