Abstract: Using glutamic acid, phosphorous acid and formaldehyde as raw materials, the glutamic acid dimethylidene phosphonic acid corrosion and scale inhibitor was synthesized in one step through Mannich reaction. The structure of the composite was characterized by infrared spectroscopy. Static weight loss method and electrochemical method were used to evaluate its scale and corrosion inhibition performance. Scanning electron microscopy was used to observe its adsorption morphology on N80 steel sheet. The results showed that the synthetic corrosion and scale inhibitor coud form a dense adsorption film on the surface of the steel sheet, inhibit the corrosion of N80 steel, and inhibit the growth of calcium carbonate on steel sheet surface. The corrosion and scale inhibitor was a mixed type corrosion inhibitor that mainly inhibited the anodic reaction. As the concentration increased, the corrosion inhibition rate increased. Under the condition of 50 ℃, the optimal addition amount was 30 mg/L, at this time the corrosion inhibition rate was 87.53%, and compared with similar products on the market, it had better CaCO₃ scale inhibition performance.