The combined effect of stresses and three environmental factors of temperature, Cl concentration and pH of a corrosive solution on the corrosion rate of bridge cable wires was investigated by stress corrosion test based on the response surface method. The stresses corrosion rate of wires is measured by the electrode polarization method using a newly-developed loading device. The relation between the corrosion rate and stresses of wires is obtained. The actual corrosion rate affected by various environmental factors (temperature, acid rain, and chloride content in air) is fitted with a response surface function. The efficiency of several functions was compared followed by significance analysis of a chosen one. The combined effect of environmental factors and stresses on the corrosion rate of wires is evaluated. As stresses increase, the corrosion rate of wires speeds up with progressive acceleration, the four factors can be arranged in descending order as to their effect on the corrosion rate of wires pH of a corrosive solution, temperature, stresses, and Cl concentration; common effect should stem from the ir combination and the range of environmental factors.