To reveal the corrosion and failure mechanisms of bolts in complex environments at the micro level, molecular dynamics methods were introduced into the corrosion research of bolts. To this end, a molecular dynamics model was established using Materials Studio, and the molecular dynamics simulations were conducted using Lammps. The corrosion characteristics of pre-stressed bolts in chloride ion environments were simulated and studied, and the micro interaction laws between chloride ion solution and the surface of bolts was explored. The results show that under the coupling effect of pre-stress and chloride ions, the iron matrix will absorb more oxygen atoms, promote the binding between oxygen atoms and iron, and accelerate the oxidation corrosion passivation of the bolts; The application of pre-stress weakens the binding of atoms inside the bolts, increasing the movement trend of iron atoms and making it easier to combine with other atoms; Chloride ions increase the strength of the interaction between iron and oxygen atoms, promoting the binding of iron and oxygen, and chloride ions will gradually become active with the increase of prestress; With the increase of pre-stress, the movement characteristics of oxygen atoms in the solution gradually weaken because they are more likely to react with iron to form stable chemical bonds. After the oxidation reaction is completed, an oxide film will form on the surface of the iron substrate. In the chloride solution environment, the thickness of the oxide layer increases significantly, and the greater the pre-stress, the thicker the oxide layer.