Abstract: Raise shaft drilling method is one of the key technologies of rapid mechanized construction of coal mine shaft. Raise shaft drilling technology is widely used in the field of large-diameter coal mine ventilation shaft engineering. Its diameter is usually greater than 5m, which brings challenges to safe construction. How to accurately pre evaluate the stability of shaft structure in the process of raise shaft reaming according to the geological data of well inspection hole is the key problem to determine the safety and engineering quality of raise shaft construction. In order to solve this problem, an evaluation method of shaft structure stability considering the technological characteristics of raise boring method is proposed. In view of the large-diameter raise shaft project represented by the ventilation shaft, the determination of the surrounding rock self stability is the key factor. Based on the strength reduction method, a quantitative evaluation method of the surrounding rock self stability ability of the shaft wall with the surrounding rock stability coefficient as the core is proposed, and the surrounding rock stability coefficient under the extreme self stability state of the surrounding rock is determined by numerical simulation. Finally, taking the return air underground shaft project of lijiahao coal mine as the research object, the local instability risk assessment opinions are put forward, and the accuracy of the assessment is verified based on the engineering practice. The results show that the assessment conclusion is consistent with the actual results.