The invention discloses a construction process of a super-large-wall-thickness super-long composite pipe manifold. The construction process comprises the following steps of S1, welding a plurality ofbranch manifolds, forming a branch prefabricated group manifold; S2, assembling and welding a plurality of main manifolds, forming a main pipe prefabricated group manifold; S3, assembling a pluralityof branch pipe tables on the main pipe prefabricated group manifold respectively, forming a connecting group manifold; S4, assembling the branch prefabricated group manifold on the connecting group manifold respectively, and then measuring levelness of the upper surface of flanges and concentricity of flange holes; S5, symmetrically welding a plurality of welding beads between the connecting groupmanifold and the main pipe prefabricated group manifold, wherein a plurality of welding beads are welded at the same time; S6, symmetrically welding welding beads between the connecting group manifold and the branch prefabricated group manifold; and S7, carrying out heat treatment after fixing the super-large-wall-thickness super-long manifold. According to the construction process, the welding sequence of the super-large-wall-thickness super-long composite pipe manifold can be controlled; moreover, the problem that the super-large-wall-thickness super-long composite pipe manifold is repairedis also avoided.