Abstract: The article relates the damage. brought by the earthquake in Feng Nan, Tangshan to QingJing pipeline. Bringing under consideration of the impact of pipe rigidity upon the indefinite deformation of soil and i ts variety on site, the author presents the formulars to computer seismic stress、which is able to give a better explanation to the actual damages the pipeline sufferd in Tangshan earth-quake. The result thus obtained is roughty the same as.what really happened in the test.