The invention discloses an integral prefabricated toilet caisson, a toilet caisson structure and a method for constructing the toilet caisson structure, the integral prefabricated toilet caisson is applied to an assembly type building, a floor drain and a node pipeline are pre-buried in a node part of a caisson groove body so that an integral prefabricated whole can be formed, the integral prefabricated toilet caisson is suitable for industrial and batch production, the construction procedure and the error can be reduced, the waterproof procedure can be completed by one time in the plant, andthe problem of leakage caused by an unqualified waterproof procedure of the construction site can be avoided; in the toilet caisson structure, only concrete of a beam cast-in-situ part and a floor slab cast-in-situ part is required to be subjected to one-time pouring forming, no horizontal construction seam exists between the integral prefabricated toilet caisson and the floor slab/structural beam, and the problem that water in the toilet leaks outward through the horizontal construction seam in the prior art is avoided; the node pipeline can be connected with a pipeline in the toilet conveniently, a pipeline installation manner of reserving a hole in the prior art is replaced, and the pipeline installation construction is more convenient, rapid and reliable.