The　erodibility　of　cohesive　and　non-cohesive　soil　mixtures　is　different　from　that　of　cohesive　soils　and　non-cohesive　soils.　In　this　paper,　erosion　tests　were　conducted　to　investigate　the　erodibility　of　three　different　non-cohesive　soil　and　silty　clay　mixtures　using　an　erosion　function　apparatus.　The　variations　of　mixtures＇　erosion　rate　and　critical　shear　stress　were　analyzed　according　to　the　experimental　data.　The　critical　mud　content　of　the　three　mixtures　were　obtained　by　analyzing　the　data　of　erosion　rate　and　critical　shear　stress.　Erosion　experiments　have　clearly　demonstrated　that　the　erosion　characteristics　of　mixtures　can　change　dramatically　when　the　mud　content　changes.　Considering　the　variation　of　mixture　erosion　behavior,　the　concept　of　degree　of　cohesive　erosion　behavior　were　proposed　for　cohesive　and　non-cohesive　soil　mixtures,　which　can　be　used　to　estimate　if　the　mixture　exhibits　cohesive　erosion　behavior.　A　formula　was　developed　for　the　degree　of　cohesive　erosion　behavior　for　mixtures.　The　formula　was　expressed　as　a　function　of　the　grain　size　of　non-cohesive　coarse　particles　and　cohesive　soil,　and　clay　content.　The　final　form　of　the　developed　formula　was　tested　using　the　experimental　data　from　the　present　study　and　the　literature.　©　2021,　China　Water　Power　Press.　All　right　reserved.