Liba gold mine is located in Lixian County of Longnan City in Gansu Province, which is one of the medium-sized gold deposit in Gansu. The stratum of mining area is complex with the existence of tectonic breccia and phyllite which have the characteristics of strong water sensitivity, and hole wall collapse happens easily. According to the characteristics of mining area stratum, the solid-free flushing fluid with characteristics of film-forming and anti-collapse has been adopted and more than 2000 meters of drill workload have been completed. The results of field application indicate that this flushing fluid system has good film-forming ability and inhibitive capacity, the hole wall collapse was successfully resolved in this mining area, and the coring recovery and coring quality are markedly improved.