The gradually reduced section of the roadway is a transitional section connecting two different roadways, which plays an important role in reducing the local ventilation resistance of the mine ventilation system. To reveal the local ventilation resistance characteristics of the roadway, the flow dynamics model of the roadway was bulit, the formula of the local ventilation resistance of the section gradual reduction roadway was deduced, and the formula was verified by the measured data. Results show that the local resistance coefficient, local ventilation resistance, and local air resistance of the gradually reduced section of the roadway are reduced by 5.71, 1.59, and 1.52 times of that of the suddenly reduced section of the roadway, respectively, which indicates that section gradual reduction roadway is in a lower energy consumption state. The conclusions obtained in the study are of great value to direct the design and construction of the similar engineering practice.