Abstract: The corrosion behavior of Q235B steel beam，ML15 steel stud，and the weldment used in a steel-concrete composite element，as well as the galvanic couples referring to the stud body in a simulated rainwater and a saturated Ca( OH) 2 solution with different amount of chlorions，was studied by electrochemical method． The results showed that the weldment was the weakest part to be destroyed in the stud-beam system，the stud head was the following one，the stud body and the beam were moderate． So the galvanic cells were easily to be established between the weldment and stud，or beam in the simulated solutions at the present work，and the galvanic current increases with the corrosion strength of the solutions． The galvanic corrosion rate of weldment was at least one order higher than that of the selfcorrosion when the galvanic cell was established．