As well known, after the infrastructure construction during the past years, it is very difficult to keep enough space to construct new infrastructure in shallow underground. The new water pipelines have to be built in deep underground. To make water pipelines construction more economy and rationalization, the separate-typed segment structure scheme was proposed and studied, which can be simultaneously build outer tunnel and inner pipe, but will leave little gap between the outer RC segment and the inner pipe. In case that great underground water pressure directly acts to pipeline, the pipeline is easily destroyed due to buckling. In this paper, we will study the buckling of water pipeline subjected to the great underground water pressure, and the design method of pipeline bucking built by separate-typed segment structure.