Abstract: The study analyzed the ventilation characteristics and problems of the Old Plant Branch of Yunnan Tin Group. Combining with the mine ventilation theory，by drawing the network diagram and the calculation of ventilation network，the multi-fan multi-station ventilation way is adopted. And the operating situation of all levels of station are compared and analyzed. Then，the paper put forward a ventilation system constructing scheme for the three new mining areas according to the principles of security，stability，technical feasibility and economical rationality. Through the analysis and comparison of the related parameters，such as ventilation lines，fan selection，installation position，quantity of air in-outlet and mining area，and the ventilation cost，the optimal scheme which was in line with the practical production was determined. 

Key words: Fan selection, Installed Point, Ventilation volume, Ventilation cost