Abstract: In order to grasp the influence of different cut-off grades on ore dilution rate and loss rate in sublevel caving mining without sill pillar，based on the stope structure parameters of an iron mine in western Panzhihua，a similar physical model of ore drawing is established，and similar simulation tests of ore drawing under different cut-off grades of 20 % and 23 % are carried out. The results show that the flow characteristics of ore rock are basically the same under the two cut-off grade conditions，and the residual ore bodies in the ridge of each segment are obviously present，which will be gradually released in the next segment. When the cut-off grade of ore drawing is increased from 20% to 23%，the ore recovery rate， waste rock mixing rate and ore dilution rate are reduced to varying degrees，and the reduction ranges are 7.94，1.77 and 1.12 perecentage points，respectively，while the recovery grade is increased by 0.44 pere⁃ centage points. Finally，it is recommended that the mine adopt 23% cut-off grade for ore drawing. The ex⁃ perimental results provide a basis for determining the reasonable cut-off grade of ore drawing in mines us⁃ ing sublevel caving method.

Key words: sublevel caving mining without sill pillar, cut-off grade, ore drawing, dilution ratio, loss ratio