The corrosion of reinforcement caused by chloridion is one of the most important factors affecting the durability of reinforced concrete. Chemical consolidation method is the main method to solve the erosion effect of chloridion on reinforced concrete structures. The stability of calcium carboaluminate under different environments was studied by X-ray diffraction analysis, thermogravimetric analysis, scanning electron microscopy and chemical analysis. The results show that calcium carboaluminate is hexagonal plate and has good thermal stability below 120 ℃. But calcium carboaluminat is very unstable in chloride and sulfate solutions, and the CO2-3 in calcium carboaluminate is easily replaced by Cl- and SO2-4 to form Friedel’s salt and ettringite. Calcium carboaluminate is unstable in acidic environment, and will react with acid chemically. It is stable in alkaline environment with pH≥11.