In order to explore the impact of the excavation disturbance on the microcrack extension, by using the combining method of elasticity and fracture mechanics, the analytic solution of the secondary stress for the lateral pressure coefficient λ is obtained based on the decomposition and superposition principles. The formulas for the extending depth of the fissure cracking are derived according to the maximum circumferential stress criterion. By building series of models of rock mechanics parameters, it is shown that the lateral pressure coefficient λ has a significant effect on the failure depth of the roadway and the stress distribution. The roadway's sides are the main regions of the surrounding rock failure under the condition of λ＞1, the roof and the floor are the main regions of the nsurrounding rock failure under the condition of λ＜1. In addition, the failure depth of the roadway has no correlation with the magnitude of the stress under a constant compression-shear stress, but dependent on the crack initial length.