The invention relates to a shield tunnel light circle-maintaining supporting system and a construction method thereof. The shield tunnel light circle-maintaining supporting system comprises a plurality of rows of supporting framed bents which are parallelly arranged in a shield tunnel in the longitudinal direction of the tunnel; the supporting framed bents are located in a vertical plane and are hexagonal star frames each constituted by six equilong supporting rod pieces, and the ends of all the supporting rod pieces are fixed to a shield segment structure; and regular hexagon areas are formedin the supporting framed bents, and longitudinal passage platforms are arranged on the positions, above the horizontal supporting rod pieces of all the supporting framed bents, in the regular hexagonareas. The shield tunnel light circle-maintaining supporting system and the construction method thereof are suitable for conducting circle-maintaining supporting treatment on areas influenced by disturbance or deformation or the like generated by the existing shield tunnel, the stability of triangles and the characteristics that a steel support is quickly mounted, is high in bearing capacity andcan be recycled are sufficiently utilized, deformation is restrained, the normal passage capacity and structural safety are guaranteed, very high operability is achieved, and industrialization operation can be achieved.