Abstract: According to the existing problems of ventilation system of slicing and back-fill mining without sub-level in downward drift in a certain gold mine，the original ventilation system is modified.A new type of “back-fill return air shaft plugging plate with expansible rigid fan tube” auxiliary ventilation device is researched and developed，and then is applied into 1111^# stope for the industrial tests.The results show that:after the ventilation system improved，the time of dust removal at each operation cycle is shortened to 0.9 h，and 32 99.4 m3 of fresh air can be saved.The problems in the process of back-fill mining without sub-level in downward drift layer are solved，such as the confounding of fresh and dirty air in the working face，and the poor ventilation effect，and the working efficiency of the stope is improved.The research results could provide theoretical guidance for improving the ventilation system of the metal mines under the similar condition.

Key words: Downward drift, Back-fill mining without sublevel, Auxiliary ventilation device, Ventilation method