A polyaspartic acid derivative (PASP-SEA-ASP) was synthesized from polysuccinimide with 2-aminoethanesulfonic acid and aspartic acid. PASP-SEA-ASP achieved a better corrosion inhibition rate for A3 carbon steel in seawater compared with polyaspartic acid (49% cf. 45% at the dosage of 100 mg/L). The development of a composite inhibitor (a mixture of PASP-SEA-ASP, zinc sulfate, 2-hydroxyphosphonoacetic acid (HPAA) and hexadecylldimethyl (2-sulfite) ethyl ammonium on a mass ratio of 15:3:6:1, respectively) led to a significantly enhanced corrosion inhibition effect, achieving an inhibition rate of 97%. The mass ratio of the composite inhibitor could be adjusted to achieve the desired corrosion inhibition rate for seawater with varying characteristics. PASP-SEA-ASP also showed excellent scale inhibition properties for seawater, with a scale inhibition rate of 100% achieved with a dosage of 14 mg/L This study demonstrated the potential of PASP-SEA-ASP to inhibit both corrosion and scale formation in domestic and industrial utilization of seawater such as cooling systems and thermal desalination processes. (C) 2015 Elsevier B.V. All rights reserved.