The invention discloses a lakebed open-excavation and concealed-burying tunnel structure with bidirectional eight lanes. The tunnel structure comprises a left tunnel, a right tunnel and a three-span structure of a pipe rack in the middle. Water pump chambers are arranged at the lowest positions of the left and right tunnels respectively, and rainwater pump chambers are arranged at tunnel openings of the left and right tunnels respectively. The tunnel structure is an integral framework mainly surrounded and blocked by a top layer, a bottom layer, a middle partition wall and side walls, wherein the top layer comprises a lake water layer, an anti-scour layer, a water-proof layer, a first die cast reinforced concrete layer and a fire-proof layer which are connected successively; and the bottom layer comprises a road surface layer, a pavement layer, a second die cast reinforced concrete layer, a water-proof layer and a cushion layer which are connected successively. By means of the lakebed open-excavation and concealed-burying tunnel structure, large-span lakebed open-excavation and concealed-burying tunnels can be achieved, the structure is safe and reliable, engineering economy requirements can be met, and risks of site construction can be reduced; and the construction speed is fast, and the construction period is saved.