The curves of recorded seismic wave on groundwater level in Shanxi water 2 and Yue 42 wells, in Tangshan city, Hebei province, are contrasted. Both wells locate in the same geological unit and same water-bearing bed, with same water level dynamic style, but have very different abilities of recording seismic wave. The mechanism of the difference in two wells is analysed from the structure of wells and the property of seismic surface wave. The result shows that the inherent period of well hole is the first important condition for influencing the ability of recording seismic wave of groundwater level in well.