Abstract: During the operation of a pipeline under pressure but no constraint, whipping effect may arise in pipeline as a result of water hammer and overpressure caused by hasty valve opening and closing, temperature variation, or earthquake. For the pipelines under the influence of vibration, corrosion, creeping and metal fatigue, severe whipping may give rise to pipeline failure and fluid leakage. Consequently, plastic collapsing may come up due to the jetting force of leaking fluid and its vibrating waves. Therefore, the preconditions to the prevention and reduction of whipping damages on pipeline are to study the originating and developing causes and to perform proper load and deformation analysis. The whipping effect and its deformation and jetting force in pipeline are introduced, deformation and load analyses are made for the whipping damages on pipeline, and the formula given for calculating the stresses in the pipeline under whipping.