Municipal tunnel engineering has developed vigorously in recent years, but many urban highway tunnels’ development are limited by construction, pipeline and other factors. In order to save land and construction period, most of them are designed as neighborhood tunnels. The most significant difference between neighborhood tunnel and separated tunnel during the construction process is that the stress state of the mid-adjacent rock is complex and the it’s stability is difficult to control. By the theoretical derivation, the instability mechanism of the soil mid-adjacent rock in shallow neighborhood tunnel is studied. Based on the bearing model of the neighborhood tunnel’s mid-adjacent rock the overburden pressure of mid-adjacent is ascertained. Combining the ultimate stress formula of the soil, the instability and failure characteristics of mid-adjacent road under different construction conditions are analyzed. Increasing the cohesion, internal friction angle and support reaction force can increase the ultimate stress of the soil, what’s more, the effect of increasing the support reaction force is more significant. Provide theoretical support for the role of supporting structure.