Abstract: With the rapid development of mining equipment， the degree of mine mechanization is getting higher and higher， and the annual electricity consumption of mine is also increasing. According to the characteristics of the production system， the power consumption links mainly include lifting， drainage， ventilation， pressure self-help and other systems. Statistical data show that the electricity consumption of mine ventilation system accounts for about 1/3 of the total electricity consumption of the whole mine. The input power of the fan is mainly consumed in the total air intake line， network in mining area and total return air line. Therefore， energy saving and drag reduction of mine ventilation system should be considered from the three aspects above. Aiming at the resistance distribution characteristics of the ventilation system in a mine， and by means of economic section method， the optimal ventilation section parameters of total return air line in a mine are put forward through economic and technological comparison and calculation verification， and the purpose of energy saving and rent reduction is easily realized. After calculation， under the premise of keeping the air flow and adopting the optimal ventilation section， the excavation and construction cost of return air tunnel in a mine was increased by 11.779 million yuan at one time， while the ventilation cost could be reduced by 88.279 8 million yuan within seven years of service with considerable economic benefits of energy saving and drag reduction.

Key words: Mine ventilation system, Energy saving and drag reduction, Total return air line, Section optimization.