Abstract: The paper, taking 3D seismic data in Inner Mongolia as an example, analyzed the reasons for the poor effect of seismic imaging of the lower part of coal seam. In data processing, surface wave and multiple wave affecting the imaging effect of the lower part of coal seam were depressed and decayed according to the space and frequency characteristics. In case of poor excitation condition, rapid decay of seismic source energy and strong shieling effect of coal seam for the lower part,weak signals were compensated and protected. The actual data processing obtained satisfactory imaging effect.