Based　on　the　large　shaking　table　test　of　saturated　sand　on　the　free　field,　the　dynamic　shear　stress-strain　response　of　the　foundation　soil　model　was　obtained　by　using　the　linear　interpolation　method　according　to　the　data　from　accelerometer　arrays.　At　the　same　time,　the　concepts　of　apparent　viscosity　and　zero　shear　viscosity　of　non-Newtonian　fluid　based　on　the　assumption　of　hydrodynamic　theory　were　introduced　to　study　the　characteristics　and　behaviors　of　shear　thinning　after　site　liquefaction.　The　characteristics　of　solid-liquid　phase　transition　of　saturated　sand　under　seismic　load　were　studied.　Results　showed　that　when　the　saturated　sand　was　stimulated　by　a　large　earthquake,　excess　pore　water　pressure　accumulated　rapidly,　and　sand　liquefaction　occurred　as　the　pore　water　pressure　ratio　of　the　upper　part　of　the　saturated　soil　ran　up　to　1.　According　to　the　variation　of　dynamic　shear　stress-strain　curve,　the　dynamic　shear　modulus　of　saturated　sand　decreased　significantly　after　liquefaction,　indicating　that　the　soil　softened　gradually.　The　variation　trend　of　shear　stress-shear　strain　rate　of　saturated　sand　derived　from　the　data　of　dynamic　shear　stress　and　dynamic　shear　strain　was　similar　to　the　rheological　curve　of　non-Newtonian　fluid.　The　apparent　viscosity　of　the　liquefied　soil　in　the　upper　part　of　saturated　sand　layer　decreased　significantly.　After　liquefaction,　the　sand　showed　the　pseudoplastic　fluid　characteristics　of　＇shear　thinning＇.　©　2020,　Science　Press.　All　right　reserved.