In order to study the pile sinking characteristics of steel sheet piles (H-shape) under vibratory loading in expansive soil layer, the test results of pile sinking depth and pile sinking rate in expansive soil layer were obtained through field tests under two different conditions, i.e. without auxiliary measures and with the auxiliary measures of "hydrodynamic method". Using finite element numerical analysis method, a three-dimensional numerical calculation model was established under the two different conditions to simulate and analyse the pile sinking process, and the ultimate depth of pile sinking in expansive soil layer was obtained, which reveals the variation rules and characteristics of the pile side friction resistance and the total pile side resistance. The results can be used to assess the reliability of pile sinking in expansive soil layer and provide quantitative reference for the design and construction of vibratory loaded pile sinking in expansive soil layer.