Abstract: The corrosion behavior of original and annealing states X80 pipeline steel was investigated in simulated acid soil solution using weight loss method,electrochemical measurement,scanning electron microscopy (SEM) and X-ray diffraction (XRD).The results show that the average corrosion rate and corrosion tendency of X80 pipeline steel in original state and annealing state both decreased,and the instantaneous corrosion rate first increased and then decreased.The corrosion products were composed of γ-FeOOH in the surface layer and Fe3O4 in the inner layer.The corrosion resistance of X80 pipeline steel decreased after annealing heat treatment because of the change of microstructure and the integrity and the compactness of corrosion product films formed on the surface of the specimen.