The paper introduces briefly features and functions of computer simulation system of ore drawing in pillarless sublevel caving (Sublevel Simulation), and analyses the features and suitable conditions of three ore drawing modes(cut-off grade drawing, dilutionless drawing and low dilutiondrawing) in pillarless sublevel caving. As a result of using SLS system to study the three ore drawing modes, it is considered that the current cut-off grade drawing mode has the highest dilution rate, and the dilutionless drawing can reduce the dilution rate to below 8% at the basically same ore recovery compared with the former method. When dilutionless drawing can' t be executed in one step, low dilution drawing can be used and the cut-off grade can be gradually reached and then transited to dilutionless drawing.