A kind of green compound corrosion inhibitor has been made from sodium molybdate, benzotriazole, calcium gluconate, sodium polyphosphate and zinc sulfate. The inhibition capability of the corrosion inhibitor in seawater for carbon steel is carried out by weight-loss method and electrochemical method. The effect of different inhibitors concentration on the corrosion efficiency is also studied. The results show that the presence of these compounds in seawater suppresses anodic processes and when the dosage of sodium molybdate is 60mg/L, benzotriazole 60mg/L , calcium gluconate is 120mg/L, sodium polyphosphate is 60mg/L and zinc sulfate is 120mg/L , the corrosion inhibition effects of carbon steel are pretty good. Carbon steel corrosion inhibition efficiency reaches 95.53% in seawater for 15 days.