The invention provides a construction method for a double-wall steel suspension cofferdam of a main bridge bearing platform of a super-large bridge. The construction method comprises the following steps that S1, steel casings are built on a river bed, and the cofferdam is assembled on the portions, above the surface of water, of the steel casings; S2, the cofferdam is laid down, and internal supports are installed in the cofferdam; S3, top-sealing concrete is poured in the cofferdam, and accumulated water in the cofferdam is drained; S4, the portions from pier bodies to the lower side of the middle internal support are built, and connecting supports are arranged between the pier bodies and the inner wall of the cofferdam and between the pier bodies; S5, the portions from the pier bodies tothe top internal support are built, and connecting supports are arranged between the pier bodies and the inner wall of the cofferdam and between the pier bodies; S6, the pier bodies are built to be above the surface of water, building of the pier bodies is completed, and building of a large bridge main pier foundation is completed. Embedded parts are arranged on the pier bodies, supporting piecesare arranged between the pier bodies and the cofferdam and between the pier bodies, the supporting pieces are connected with the embedded parts, the support of the interior of the cofferdam is enhanced, and the structural strength of the cofferdam is ensured.