The invention discloses a support structure for hard rock large-section tunnel construction, and a construction method for the support structure. The support structure comprises an initial support and a temporary support which consists of a plurality of vertical temporary supports and longitudinal temporary supports which are connected with the initial support of a tunnel arch crown, wherein the vertical temporary supports are arranged on a tunnel central line between the tunnel arch crown and a tunnel spring line and the bottoms of the vertical temporary supports are supported on unexcavatedrock on the spring line and are not needed to extend to the bottom of the tunnel section. The support structure solves the problem that support processes are complex and slow and the temporary supports are damaged seriously during blasting in the multistep blasting and excavation construction of (especially) large-section hard rock, and has the advantages of simple structure, quick construction progress, high construction safety and capacity of reducing damage of hard rock blasting to a temporary support system to the maximum extent, and the like.