Abstract: The uniform corrosion rate of Q345R steel in simulated formation water containing different amounts of elemental sulfur (0, 5, 10, 20 g/L) at 60 ℃ was measured by weight loss method. The microscopic morphology of the soaked sample was characterized by scanning electron microscope (SEM). The electrochemical behavior of Q345R steel in simulated formation water containing elemental sulfur was also studied by electrochemical method. The results showed that the presence of elemental sulfur accelerated the corrosion of the steel. With the increase of sulfur content in the water, the average corrosion rate of the steel gradually increased from 0.2778 mm/a to 1.0261 mm/a. It is considered that with the increase of sulfur content, the charge transfer resistance of the material was reduced and the cathodic reaction was accelerated; At the same time, elemental sulfur could cause pitting of Q345R steel and so increase localied corrosion risk.