In the process of upward medium-length hole blasting in underground mines,the damage of surrounding rock at the brow is mainly caused by the blast of the last row of blast holes.The angle of blast holes,the length of air decking and the spacing of blast holes are important and easily adjustable blasting parameters that affect the control effect of the brow.To ensure the integrity of the brow and the safety of the blasting working face,the optimization of these aforementioned blasting parameters are studied.Taking the blasting in the underground stope of Tonglushan Mine as the engineering background,the blasting numerical models with different blast hole angles,air decking lengths and blast hole spacings are calculated and analyzed by the blasting crater theory and LS-DYNA.The calculation results show that the smaller the blast hole angle is,the better the integrity of the rear brow is protected.The air decking can effectively reduce the brow damage.When the hole spacing is 1.0 m,the smooth brow contour can be ensured.Considering the control effect of brow and the site conditions,the optimal blast hole angle,the optimal air decking length,and the optimal blast hole spacing are determined as 80°,0.6 m and 1.0 m,respectively.According to the analysis results,the field blasting tests were carried out in Tonglushan.The field results show that the integrity of the rock mass in the brow region,roof and two sides are good,and the rock damage is minimal.Besides,the blasting fragmentation is uniform,and the blasting effect is positive.