In order to investigate the effect of different stresses on the corrosion behavior of Q345B low carbon steel, which had been immersed in a sedimentary water environment for 24 days. In this paper, the pressure of 0, 160, 320 MPa was applied to the materials by the C-ring model, and the corrosion behavior of Q345B low carbon steel was observed and analyzed by electrochemical impedance spectroscopy(EIS) and Mott-Schottky curve. The micromorphology was observed by scanning electron microscope(SEM). The results show that there is a certain interaction between the corrosion medium and the applied stress. After the stress is applied, the surface charge of the film changes significantly, and the corrosion rate of Q345B low carbon steel increases significantly.