The work aims to reveal the corrosion behavior and regularity of X80 pipeline steel in wetting-drying alternating and water saturated Hami soil. The weight loss experiment and electrochemistry test were used to analyze the change law of the corrosion rate and electrochemical process of cathode/anode. The metallographic analysis was used to observe the structural characteristics of base metal and welding sample. The microstructure, element content and phase composition of corrosion products were observed by SEM, EDS and XRD to explore the effect of wetting-drying alternating and water saturated soil on the corrosion behavior of X80 pipeline steel. The corrosion rate of X80 pipeline steel in wetting-drying alternating soil was 2~3 times higher than that in water saturated soil. The phase composition of the corrosion products in water saturated and wetting-drying alternating Hami soil consisted of Fe3O4, FeOOH and FeS. For the X80 pipeline steel in the wetting-drying alternating soil, a large number of pits and cracks appeared on the corrosion product film of the sample surface, resulting in the uneven distribution of O2 on the sample surface and the formation of oxygen concentration cell and the pits and cracks were conducive to the entry of corrosion ions, aggravating the local corrosion. In the same circumstances, the corrosion rate of X80 steel welding sample was obviously higher than that of X80 steel base metal, which was mainly caused by the galvanic corrosion induced by the difference of the microstructure of welding joint. The presence of a large amount of Cl- in wetting-drying alternating soil circumstance accelerates the local corrosion of X80 steel base metal and welding sample and the corrosion resistance of X80 steel welding sample is obviously lower than that of X80 steel base metal. The corrosion mechanism of X80 steel is the combination of oxygen concentration cell and local corrosion autocatalytic effect. The corrosion morphology is changed from general corrosion (water saturated circumstance) to pitting corrosion + ulcerated corrosion (wetting-drying alternating circumstance).