Abstract: The mining design of deposit is a typical mining engineering.It has important realistic meaning to optimize the stage height by using the system engineering thoughts along with the modern information technology.Based on the design function of 3DMine software，the optimal system of stage height is built including inputting，modeling，calculating and outputting.Then，3D visualization and space optimizing of underground engineering are realized to complete the mining optimization of one mine.The optimizing system is mainly based on 3D models of the mining development system，and selects the better stage height from several plans.According to the principle of minimum driving per unit，the optimal stage height is selected.A research on optimal stage height of a multi-layer deposit is consistent with the actual situation，which verifies that the optimal system is feasible and practicable.

Key words: 3DMine, Stage height, Optimal system, Multi-layer deposit