The corrosion of rebar in concrete was studied by 4×4 liner wire - beam electrode. The corrosion potential distribution of wire - beam electrode in different depth was obtained by testing corrosion potential in 1.9 mol/L NaCl solution. The effect of different additive on cement was also studied. The results showed that the corrosion of iron wires in ordinary concrete was asymmetrical, and the corrosion potential value was scattered, and with the immersion time increased, the corrosion potential move to negative; adding 0.25% sodium lignosulpho...