Abstract: In order to solve the problem of mutual interference between the main fans in multi-fan joint operation, this paper put forward the principle of defining two typical public airways, qualitatively analyzed the influence of the proportion of the the air resistance of the public airways in the total air resistance upon the whole ventilation system, and pointed out that the reasonable proportion of the air resistance of the public airways in the total air resistance was not a fixed value. Based on the practical situation of a mine and through the system modeling, the ventilation network calculation and empirical analysis, it was found that the problem was the too long public air way of the ventilation system of the mine, this thus provided theoretical basis for the transformation of the mine ventilation system.