Abstract: Good and bad of the mine ventilation system is generally from a comprehensive evaluation of the technical, safety and economy, and it should achieve basic principles of feasibility in technique and reasonability in economy, safety and reliability. Taking a coal mine in Guizhou for example, by analyzing the problem of ventilation system, the paper puts forward rectify and reform ways, makes use of AVENT software for network calculation, and analyzes the result. At last, the paper gets the best ventilation scheme and chooses the reasonable main ventilator.