Abstract: To ensure the steadiness and high efficiency of gas drainage,the resemble simulation and numerical simulation test are adopted to study the distribution characteristics of overlying strata mining fissure field and gas field on the process of cross pitch mining and cross dip mining for coal seam.The distribution characteristics of mining fissure around goaf is identified and the roof caving range is divided into three regions along the working face,it determines the best area of high level boreholes.On this basis,it establishes the optimized design process and system for high level boreholes,obtains the parameters determining methods by the theoretical analysis.