Abstract: By taking the geological conditions of N2103 working face inWangjialing Mine as the engineering background, the mechanical model of the main roof fracture was established based on the theory of the elastic foundation beam, and the specific expression of the bending moment was derived. The research results showed that the tensile stress in the main roof was proportional to the bending moment of its corresponding position, and the place with the maximum bending moment was the fracture position of the main roof, which was basically consistent with the survey results obtained by the field borehole peeping instrument. Using this mechanical model can better predict the fracture position of the main roof above the gob-side entry, and then provide the basis for the safety design of the pillar width of the gob-side entry, so it has a certain guiding significance for the surrounding rock control with the similar engineering conditions.