The utility model provides a connecting structure which comprises a bottom plate, a first clamping piece and a second clamping piece, the first clamping piece and the second clamping piece are arranged on the bottom plate in a spaced mode in the first direction, the first clamping piece and the second clamping piece are used for clamping a rail between the first clamping piece and the second clamping piece, and the first clamping piece comprises a first side plate, an outer
flanging, an elastic abutting plate and a bolt. One end of the first side plate is connected with the bottom plate, an outer
flange is arranged at the end, close to the bottom plate, of the first side plate, the end, away from the bottom plate, of the first side plate is connected with the elastic abutting plate, a through hole is formed in the elastic abutting plate, a threaded hole corresponding to the through hole is formed in the first side plate, and a bolt penetrates through the through hole to be screwed into the threaded hole. And the elastic pressing plate can tightly press the outer
flanging on the track by screwing the bolt. The utility model further provides a water tank connecting piece, a track connecting piece and a photovoltaic support applying the connecting structure, and through the connecting structure,
assembly and disassembly of the track and the water tank are more time-saving, labor-saving, convenient and rapid.