The ventilation system in deep mining is faced with high temperature, long ventilation line, complex network and insufficient pressure of main fan, etc. Reforming design is necessary. Taking the two stage deep mining of a lead-zinc mine in Hunan as an example, the deep ore body is to the south side with high sulphur content, and releasing large heat, the ventilation has long line and large resistance, the main fan is low, the fresh air quantity is insufficient and the heat is difficult to expel, which seriously affects the safety production of the mine. In order to solve the difficult problem of mine ventilation, the key problems existing system are analyzed on the basis of field investigation and determination, and the modification scheme of parallel return air with multi-level drift and multi-shaft are put forwards in deep mining ventilation, The multi-shaft parallel return network is formed by using auxiliary inclined shaft, small shaft and return air well, and two levels transportation lanes in the end upper part are used as the return air passage of the deep mining, which can effectively reduce the ventilation resistance. The scheme makes full use of the existing projects, with less investment and quick effect, and good results in engineering application are obtained, that can be used for the similar transformation in ventilation system.