Steam turbine and stator blade thereof

According to the steam turbine and the stator blade thereof, the back arc surface of the stator blade is provided with the step surface, a water film can be broken to form large liquid drops capable of directly entering the throat area along with steam, the large liquid drops are torn into small liquid drops in the throat area, and the small liquid drops can be the same as or similar to a steam flow path; the scouring of the liquid drops to the air inlet edge of the moving blade is reduced, so that the etching and mechanical impact of the moving blade are reduced, and the use performance and the service life of the moving blade are greatly improved. 本发明提供了汽轮机及其静叶片，本申请中所提供的静叶片的背弧表面具有台阶面，能够将水膜打断并形成能够直接随蒸汽进入喉部区域的大液滴，大液滴在喉部区域被撕裂碎化成能够与蒸汽气流流动路径相同或相近的小液滴，降低了液滴对动叶片进气边的冲刷，进而减缓了动叶片的浸蚀和机械冲击，大大提高了动叶片的使用性能和使用寿命。