Abstract: With the continuous growth of China's power demand, 1000 MW thermal power units serve as the main power generation equipment, making their operational stability and reliability crucial. The low-pressure last-stage blades of steam turbines, operating in wet steam areas, are highly susceptible to water erosion, leading to blade damage and affecting the safe and stable operation of the units. Aiming at the water erosion problem of low-pressure last-stage blades in 1000 MW ultra-supercritical thermal power unit steam turbines under high-humidity steam environments, this paper conducts research from three aspects: Water erosion mechanism, protection technology system, and engineering application cases. By analyzing the working conditions and damage forms of the last-stage blades, a collaborative protection strategy of "material-structure-operation and maintenance" is proposed. Combining new coating technologies, structural optimization, and intelligent monitoring methods, this paper details solutions to enhance blade service life, aiming to provide references for improving the water erosion resistance of low-pressure last-stage blades of steam turbines.