Due to the influence of the high intensity mining operation in the Shendong mining area located in Ordos City, Inner Mongolia Region of China, the problem of rib spalling in large mining height and fully-mechanized working face production is increasingly becoming more serious. The occurrence and location of the maximum depth of rib spalling is studied inthe 12301 working face of Shangwan coal mine in the Shendong mining area taken as an example. The comprehensive methods of theoretical analysis, numerical simulation and field studies are adopted in this study. The gradual deterioration characteristics of rib spalling was studied using the ‘thin plate’ mechanical model of the working face and the empirical equation. The study showed that the rib instability was generally located below the roof at the position of 0.578 times of the mining height. The theoretical calculation showed that the maximum depth of rib spalling was 0.98 m~1.61 m at the 12301 working face, and the initial rib spalling started 2.53 m below the roof, which is basically consistent with the results of the numerical simulation and the statistical analysis of data from the field. The study provides the foundation for the future control measures of rib spall.