Abstract: In order to realize the on-line and accurate measurement of roadway air volume, taking the return air roadway and auxiliary transportation roadway in Shangsitou north wing of Wangpo Coal Mine as the research object, the wind speed structure field of rectangular roadway and semi-circular arch roadway section was simulated by CFD method, and the regional distribution of average wind speed in roadway section under different air volume conditions of the same roadway section was compared. The air volume basically had no effect on the regional range and location of the average wind speed distribution of the roadway section and the dimensionless wind velocity structure field of roadway section was further obtained, which was the theoretical foundation for arranging multiple wind speed collection points in the roadway section average wind speed distribution area to accurately calculate the roadway average wind speed. Based on the dimensionless wind speed structure field of roadway section, the position of data acquisition point of roadway average wind speed was determined according to the distribution area of roadway section average wind speed, and the nine point acquisition method of roadway section average wind speed was constructed, which could accurately obtain the roadway average wind speed and check whether there was data distortion in the wind speed sensor. Combined with the nine point acquisition method of roadway section average wind speed, the gantry and folding fully automatic on-line test device for roadway air volume suitable for rectangular roadway and arch roadway were designed respectively. The structural size of the test device and the motion track of wind speed sensor were customized according to the position of roadway average wind speed data acquisition point. The fully automatic on-line test device for roadway air volume was deployed at 10 wind measuring stations in Wangpo Coal Mine. The relative error between manual wind measurement and device wind measurement data was less than 8%. The research showed that the wind measurement accuracy of the fully automatic on-line test device for roadway air volume could meet the mine requirements, and could realize the synchronous on-line measurement of the air volume of multiple roadways in the mine.