To define the relationship between initial state and safety of pipeline shutdown under the progress of forward and reverse transporting, the forward and reverse stages have been divided into 4 stages:forward cold oil control stage, forward hot oil control stage, reverse cold oil control stage, reverse hot oil control stage.And under the analysis of pipeline temperature drop on different running stages, qualitative analysis on safety of different initial state of pipeline shutdown is carried out from oil temperature changes.Lastly, a new variable “safe shutdown probability” is defined.Quantificationally, the initial state safety of pipeline shutdown on different moments of oil forward and reverse transporting is analyzed.It turns out that while, shutdown is of the lowest safety; while, shutdown is of the highest safety.