The corrosion behavior of Ni-P coating deposited on 3003 aluminum alloy in flue gas condensate was investigated by electrochemical approaches. The results indicated that nitrite acted as a corrosion inhibitor. The inhibiting effect of nitrite was reduced in solutions containing sulfate or nitrate. Chloride and sulfate accelerated the corrosion of Ni-P coatings greatly. This can provide important information for the researchers to develop special Ni-P coatings with high corrosion resistance in the flue gas condensate.