The invention discloses a steep-dip ultra-thick coalbed mining technique based on top-coal advancing pre-detonation weakening. The steep-dip ultra-thick coalbed mining technique includes exploiting steep-dip ultra-thick coalbed from back to front along coalbed bearing in several exploiting periods. In one of the exploiting period, the steps include firstly, constructing a roadway; secondly, weakening top-coal advancing pre-detonation, to be specifically, 201, determining a coalbed to be detonated; 202, drilling blast holes from an intake airflow road by a drilling machine; 203, charging and sealing the blast holes; 204, detonating for the first time; 205, detonating for the second time; thirdly, exploiting the coalbed; fourthly starting the next exploiting period; repeating the fourth step for many times until the steep-dip ultra-thick coalbed is completely exploited. The steep-dip ultra-thick coalbed mining technique is simple in steps, reasonable in design, high in exploitation efficiency and working-face recovery ratio, and good in using effect, and the problem that an existing mining technique is complicated, low in working-face recovery ratio and low in exploitation efficiency and causes many potential safety hazards is solved.