Abstract: The electrochemical corrosion behavior of X80 pipeline steel was investigated in Yan′an soil with saturated water by using electrochemical measurement,scanning electron microscopy and energy dispersive spectrum analysis.The results show that the corrosion rate of the steel decreased first then increased with the prolongation of corrosion time,and the corrosion tendency increased.The corrosion morphology on the steel substrate was changed from uniform corrosion to localized corrosion.The corrosion mechanisms were oxygen-concentration corrosion cell and localized corrosion autocatalysis effect,and the corrosion rate was controlled by oxygen diffusion process.The corrosion product was main iron oxides.