The invention provides a construction method for a support combining steel sheet piles and stirring piles. The method is characterized in that the soil blocking performance and the good permeability resistance of the cement stirring piles and the waterproof performance and the flexural behavior of the steel sheet piles are adopted for manufacturing a support structure of underground deep foundation pits, and particularly includes the following steps that (1) a stirring pile machine is used for stirring underground, a structure with loose soil at the upper portion and the cement stirring piles at the lower portion is formed, and the distance between the pile tops of the cement stirring piles and the design bottom faces of the foundation pits is +/-0.5 m; (2) before the cement stirring piles are hardened, the steel sheet piles are sunken into the loose soil and are meshed to form a closed steel plate pile wall, and the steel plate piles are downwards in lap joint with the cement stirring piles, wherein the steel plate piles are coated with an antifriction agent before pile sinking; and (3) excavation of the foundation pits and installation of enclosing purlins are carried out in a zone defined by the steel plate pile wall, and excavation of the foundation pits and installation of the enclosing purlins are alternatively carried out.