Abstract: In order to study the failure mechanism of roadway surrounding rock under horizontal structural stress, we analyzed the influence of roadway span on the stability of roadway surrounding rock based on the pressure arch theory, theoretically analyzed the horizontal tectonic stress influence on roadway roof and two sides, and simulated the different roadway cross sections and horizontal stress of the roadway surrounding rock stress and displacement distribution through the establishment of PHASE2D numerical model, it shows that the increase of roadway span has a great influence on both sides of roadway roof, which makes the horizontal and vertical stress concentration coefficients increase, the strength coefficient decrease, and the surrounding rocks on both sides of roadway roof are more vulnerable to instability and failure. With the increase of side pressure coefficient, the strength coefficient of two sides of roadway decreases in a large range, it indicates that the increase of horizontal stress will cause the failure of two sides of coal body. At last, we verified the theoretical analysis results by the specific case list, and proposed a reasonable support scheme.