Abstract: Speedy drivage urgently needs to build a high-precision two-dimensional geological model. Taking the XY-S working face of Qinshui coalfield as an example, based on the results of 3D seismic interpretation, the coal seam floor elevation measured during excavation is used to update in succession the 3D seismic average velocity field and the coal seam floor elevation ahead, thus the prediction accuracy ahead of heading is analyzed statistically. The results show that the error between the predicted coal seam floor profile and the actual exposed profile decreases gradually by constantly making use of the measured coal seam floor elevation, upgrading the average velocity field and mapping the geological section in front of the drivage. The minimum absolute error of floor elevation in the range of 25 m and 50 m ahead of the measured point is as small as 0.2 m and 0.45 m respectively. The prediction accuracy will be further improved if the measured points data become larger in density and evenly distributed, and it can provide high-precision coal seam floor navigation data for speedy drivage.