This paper takes Shenyang metro engineering with sandy soil for background, and the ground settlement induced by shielding tunneling construction is predicated and analyzed. Make clear the influential areas of lateral settlement in accordance with the monitoring data. Use traditional Peck Formula to fit actual settlement curve of the cross-section. From the curve fitted by Lagrange interpolation function, the half width i of the settlement tank can be gained. And then calculate the volume of the settlement tank, the improvement factor k and volume loss rate VL. The Peck Formula with improved factors can suitably predict the ground surface settlement.