In this article first order second moment and Monte-Carlo methods are used to calculate the reliability of the pipeline under uniform corrosion conditions. The results show that the data obtained by the two methods is almost the same. Reliability assessment shows that the reliability is continuously decrease while the stress of the pipeline is still lower than yield limit of the material. At the 20th year in the pipeline’s life, the reliability is only 0.58, and the pipeline is not safe anymore. So, for the safety of the pipeline, not only the stress should be considered, but also the reliability.