Polyaspartic acid（PASP） was synthesized by polycondensate of L-aspartic acid using H3PO4 as a catalyst. The corrosion inhibition performance of PASP on carbon steel was studied by a rotating hanging slice method. The results showed that the corrosion inhibitory efficiency rose with the increasing of the concentration of PASP. It also indicated that the highest corrosion inhibitory efficiency reached 93% when the concentration of PASP was 100 mg/L. The strong adsorption signal of PASP on the carbon steel surfaces was detected by surface-enhanced Raman scattering（SERS） technique. The results suggested that the high corrosion inhibitory efficiency appeared owing to the chemical adsorption of carboxyl groups in PASP on steel surface.
