Abstract: There is a big difference between the main ventilator′s theoretical characteristic curve and practical curve in Lubanshan South Mine，and the designed air volume of the mine is smaller than the actual air volume，while the designed mine ventilation resistance is larger than the actual mine ventilation resistance，resulting in the fan operating point being at an obviously unreasonable point at present：Fan has no surplus capacity with low efficiency.First from the optimization of the ventilation line，three ventilation schemes are put forward，two of which feasible schemes being calculated by ventilation network calculation software.By qualitative comparison of ventilation network calculation results with several other aspects，the optimal scheme is determined，namely，the plan of three intake one return.In combination with the selected optimal mine ventilation system，considering the technical feasibility，operation cost and investment cost of the mine main fan consideration，it is proposed that the existing two sets of rotary explosion-proof axial flow type main fan is technologically transformed，i.e.，changing fan blade and replacing its motor，and then the main fan with larger ventilation capacity is used in later period，combining with the ventilation reform at the second level.

Key words: Fan characteristic curve, Ventilation capacity, Network solution, Ventilation Transformation