Abstract: This paper investigates how the selection of weathering zone velocities is in control of static correction in moutain areas around Zhunger Basin. The paper proposes to calculate the to value for a bedrock Just beneath the weathering zone by making use of firstbreaks extracted from a reciprocal obserxration in a seismic multiple coverage system. In that case, as long as a good weathering velocity is selected, high magnititude statics caused by the inhomogeneity near surface and the undulation of the bedrock are reduced to a great extent so as to make the errors in static correction to be confined within an extent as required by the automatic static correction. As a consequence, the velocity analysis and horizontal stacking processing that follow are definitely improved.