The work aims to reduce the harm of corrosion on operationoil and gas pipelines. In the soil simulation solution of Liaohe Oilfield, soil simulation solution with different dissolved oxygen concentration was obtained by controlling different nitrogen pass-through time in the solution. The influence of different dissolved oxygen concentrations on electrochemical corrosion behavior of X70 pipeline steel in soil simulation solution of Liaohe Oilfield was studied by AC impedance technology and potentiodynamic polarization technology. In order to clarify the mechanism of the different concentrations of dissolved oxygen on the corrosion behavior of pipeline steel, the corrosion morphology of the pipeline steel surface was characterized with a metallographic microscope. In such environment, the corrosion mechanism of X70 steel was anodic dissolution mechanism. With the continuous decrease of dissolved oxygen content, the polarization resistance of the electrode becamelarger and the corrosion current density decreased. At this time, the number of pits on the surface of the electrode also decreased, the pit diameter became smaller, and the metal corrosion rate droppedsignificantly. When the dissolved oxygen concentration was 10.0 mg/L, the corrosion rate of the specimen was the largest, and the corrosion phenomenon was most obvious. When the dissolved oxygen content reduced from 10.0 mg/L to 0.3 mg/L, a layer of corrosion product mainly containing FeCO3 was formed on the surface of the metal electrode. The product film significantly inhibited the corrosion reaction and protected the X70 steel. At this time, the corrosion of the sample wasthe least obvious. The difference in dissolved oxygen concentration leads to different morphologiesof the product film on the surface of the X70 pipeline steel electrode and then affects the electrochemical corrosion behavior of the metal in the environment.