In　this　paper,　the　water　droplet　erosion　(WDE)　performance　of　typical　martensitic　precipitation　substrate　0Cr17Ni4Cu4Nb　in　steam　turbine　final　stage,　laser　solid　solution　strengthened　sample,　laser　cladding　sample　and　brazed　stellite　alloy　samples　have　been　studied　based　on　a　high-speed　rotating　waterjet　test　system.　The　WDE　resistance　of　several　materials　from　strong　to　weak　is　in　sequence:　Brazed　stellite　alloy　＞　laser　cladding　sample　＞　laser　solid　solution　sample　＞　martensitic　substrate.　Furthermore,　the　WDE　resistance　mechanism　and　the　failure　mode　of　brazed　stellite　alloy　have　been　revealed.　It　is　found　that　the　hard　carbide　in　the　stellite　alloy　is　the　starting　point　of　crack　formation　and　propagation.　Under　the　continuous　droplet　impact,　cracks　grow　and　connect　into　networks,　resulting　in　the　removal　of　carbide　precipitates　and　WDE　damage.　It　is　proved　that　the　properties　of　the　Co-based　material　itself　is　the　reason　for　its　excellent　WDE　resistance.　And　the　carbides　have　almost　no　positive　contribution　to　its　anti-erodibility.　These　new　findings　are　of　great　significance　to　process　methods　and　parameter　selection　of　steam　turbine　blade　materials　and　surface　strengthened　layers.　©　2020　by　the　authors.