Abstract: Based on disasters due to earthquake, two model-beam-type dynamic instability and Shell-type dynamic instability for two types of dynamic instability of buried pipelines in axial direction are put forward,and equation for the dynamic instability of buried pipelines are established. The models regards the pipeline as long beam and circular cylindrical thin shell buried in elastic half-space. The soil-pipeline interaction is obtained by combining the dynamic plane strain solution with the static Mindlin solution. Taking buried gas pipelines in city and long oil-pipelines in our country as examples, parametric studies are carried out,and some conclusions are obtained, and reasons for disasters are explained.