Abstract: The pressure relief gas extraction is closely related to the evolution laws of mining fissure in overlying strata. We use similar simulation experiment to analyze movement laws of overlying strata containing fault, distribution laws of fissures and morphological characteristics in a coal mine of Guizhou province. The results show that the fissures in overlying strata experience the process of generation, development, close with the advancing of working face; fractures increase significantly near the roof fault and the fracture density curve is “Mountain” type distribution. The height of fissure is obviously affected by key stratum and roof fault.