The characteristics and design theory of PVC sheet piles as supporting structuresfor foundation pits are studied.The manufacturing process of PVC sheet piles was expo un-ded， and the material properties of PVC sheet piles and steel sheet piles were compared andanalyzed.On this basis， the modulus of PVC sheet piles is appropriately reduced， and atwo-dimensional numerical model of PVC sheet pile cantilever and single-supported found a-tion pit support is established.The effects of different supporting structure forms， soilstrength and other factors on the maximum supporting depth and minimum embedded depthof PVC sheet pile retaining structure are discussed.The research results show that the PVCsheet pile has smallstiffness and creep property，and application to long-term supportstructures should be based on a design method controlled by deformation.PVC sheet pilecantilever support is suitable for support depth of 1~3m， and single support point support is suitable for support depth of 1~5m.The maximum support depth of PVC sheet piles isapproximately linear with the cohesion force， and the foundation pit support structure hasthe greatest influence on the PVC sheet pile foundation pit support system.