Survey to shallow underground water is a part of geochemical survey in lower reach of the yellow river.After collecting one sample in every 16km2,33 kinds of indices are determined,such as As,Ba,Be,Ca,Cd,Co,Cu,Fe,Hg,Pb,Se,Zn,F-,Cl-,Cr6+,NO2-,COD and pH,etc.Through study on background variation rule of these indices in shallow underground water,it is regarded that each index varies greatly and has rich concentration,especially the variation indices of some ratios are all more than 3.0,such as As,Fe,K,La,Sb,S...