The invention discloses snowflake steel sheet piles and a machining and construction method thereof. Each steel sheet pile comprises a pile body, supporting plates located at the upper end of the pilebody and a pile cap located at the top end of the pile body. The snowflake steel sheet piles are built in sections, and steel plates are laid on the steel sheet piles after building the snowflake steel sheet piles to enable pile groups to be connected integrally. Compared with the prior art, the snowflake steel sheet piles and the machining and construction method thereof have the advantages that(1) the bearing capacity of pile shafts is increased by the snowflake pile bodies; (2) the whole stiffness of the steel sheet piles is enhanced by an axisymmetric star design, and pile deformation iscontrolled effectively; (3) the arranging positions of the supporting plates conform to the law of stress diffusion of soil around the piles to be conductive to enabling the pile shafts to be stressed fully and enable the pile shafts to reach a small settlement; (4) the snowflake steel sheet piles are built at the bridge head of a highway bridge which is opened to traffic, the steel plates are laid at the tops of the piles, and differential settlement of the bridge head can be effectively controlled; and (5) the steel sheet piles are built in sand soil and soft soil areas by a crane, the steel plates are laid on the steel sheet piles, heavy machinery can enter quickly, the construction period is shortened, and the engineering efficiency is improved.