The bioleaching behavior of low-grade copper sulphides under the condition of preferential solution flow was investigated through experiments.The experiment of bioleaching was conducted within the multifunction autocontrol bioleaching apparatus.The results show that the concentrations of Cu2+ and total Fe increase slowly at the beginning.The recovery rate decreases with the increase of depth of dump.The preferential solution happens within the fine region when the application rate is low,and the recovery rate of the fine region is higher than that of the coarse region.The content of fine ore particles within both fine and coarse regions increases during the leaching period,and the preferential solution flow shifts from fine region to coarse region.The surface of the ores at the top of dump is attacked seriously,and the ores in the middle is attacked slightly.There are plenty of crackles on the surface of bottom ores because of the precipitation layer on the surface.