Abstract: Two damage cases of a water supply pipeline under the fault movement in Turkey Earthquake and Ji-Ji Earthquake are studied with an improved finite shell element model. An analytical model is given in this paper. The behavior of the pipe segments far from the fault is substituted by an equivalent boundary proposed by the authors. Therefore, only the pipe segment near the fault is modeled with shell elements. Compared with the beam model, the shell model can examine various failure modes of the buried pipeline under a fault movement more clearly. Considering the difference between soil conditions on two sides of the fault in the shell model, three buckles of Izimit water supply pipeline(Φ2200)in Turkey Earthquake and two buckles of water supply pipeline(Φ2000)in Ji-ji Earthquake are numerically simulated successfully. The reason for the three buckles observed in Izimit water supply pipeline is discussed.