The invention belongs to the field of buildings and particularly relates to a water area tunnel formwork supporting structure and an integral sliding structure of an internal formwork support. The water area tunnel formwork supporting structure comprises a concrete bottom plate poured in advance, external formwork supports constructed at two sides of the bottom plate and used for forming external formworks, the internal formwork support constructed on the bottom plate and used for forming an internal formwork, the external formworks fixedly arranged at the inner sides of the external formwork supports, the internal formwork fixedly arranged at the outer side of the internal formwork support and split steel bars split between the external formwork supports and located above the external formworks; a connecting steel bar of which one end is pre-embedded into the bottom plate and the other end extends out of the bottom plate and is connected with each of the external formwork supports is also connected between each of the external formwork supports and the bottom plate; and a Bailey truss non-through split screw formwork supporting technology is adopted for solving the problem of easily-caused water permeability and leakage of the traditional waterproof through split bolt pull side wall, avoiding influences to the durability of a wall body due to the water permeability and leakage and improving the structural integrality on the premise of guaranteeing the workability and is a scientific, economic and environment-friendly external side wall formwork supporting technology.