Abstract: A new type of coolant was developed for the converter of large wind turbines. The physical and chemical properties of the new coolant were analyzed, and the corrosion resistance of 6063 aluminum alloy in the new coolant was investigated through weight loss tests, electrochemical tests, and scanning electron microscopy. The results indicate that the addition of a composite corrosion inhibitor with chelating effect on metal ions such as copper and iron in the new coolant played a synergistic effect. The new coolant had a good corrosion inhibition effect on 6063 aluminum alloy.