The corrosion behavior of X80 pipeline steel in simulated solution of southeastern acid soil was investigated using electrochemical measurement, scanning electron microscopy (SEM), energy dispersive spectrum (EDS) and X-ray diffraction (XRD). The effects of heat treatment process and corrosion time on the polarization curves were analyzed. The results show that the change of microstructure by annealing treatment accelerates the corrosion of X80 steel, which is worse than that of original state, the corrosion rate increases first and then reduces. The cathodic reactions are dominated by oxygen reduction and hydrogen evolution reaction. The corrosion products consist of FeOOH (surface layer) and Fe_3O_4 (inner layer). The integrality and compactness of corrosion product films influence the corrosion process, and increase the corrosion damage of X80 steel surface. The content of Cl~- dominates the corrosion severity.