Abstract: Operation safety of pipelines will be seriously threatened by pressure fluctuation. Therefore, the cyclic statistics about the fluctuation course of operation pressure for 5 inland oil & gas pipelines have been done by using the rain-flow counting method. The cycle number and amplitude of pressure fluctuations are analyzed. And the characteristics and causes of pressure fluctuations for the different type of pipes are also discussed. The authors present specific solutions and operational measures in the paper. Results show that the influences of transport medium, service life and external operating conditions are different for different pipelines, so the number, pressure ratio and fluctuation amplitude of pressure cycles are all different. For example, for newly-constructed pipeline, the cycle numbers of pressure fluctuation are relatively more with larger fluctuation amplitude. And the pressure fluctuations of oil/gas pipelines are quite different during smooth operation. The minor fluctuation in gas pipeline is obviously more than that of oil pipeline. So the risk of stress corrosion is higher. Because of the differences of various data collection methods, a big impact on the analysis accuracy of the pipeline pressure fluctuation will occur. Under this case, 3 principles to select the process of data collection methods are needed to be adopted. Suggestion to adopt the rain-flow counting method to conduct a regular statistical description to the pressures that pipeline has been subject to is presented so as to take measures to reduce damages to the pipeline based on the running conditions and fluctuation causes of pipeline.