Abstract: Based on the corrosion method of electricity migration，the characteristics of the chloride ion transmission under the stray current environment in the concrete cover were researched． Through four groups of specimens，the variation characteristics of the chloride ion concentration in concrete cover in the case of different current intensity and power-on time were researched in the test． This paper mainly analyzed the influence rules of chloride ion transmission in concrete cover and the chloride concentration on concrete surface under the action of electric field． The results showed that the chloride ion concentration in concrete cover evolved from non-steady-state transmission to steady-state transmission in several hours under the action of the electric field． Its transmission efficiency was 900 times higher than the free diffusion results． But the chloride ion concentration dropped with the increase of power-on time，not stable in the steady-state transmission stage． The growth rules of the concrete surface chloride ion concentration were significantly different from general chloride environment before the chloride ion concentration in concrete cover turn to steady-state transmission． It dropped in power function with the increase of the power-on time，growed in power function with the increase of the current intensity． And the power-on time is the more important factor．