Ultrathin-wall steel structure connecting piece and connecting structure thereof

The utility model discloses an ultrathin-wall steel structure connecting piece and a connecting structure thereof. The connecting piece is a hollow cube or a rectangular connecting piece, a front side plate and a rear side plate of the connecting piece are two pieces of channel steel buckled with each other, an upper side plate and a lower side plate of the connecting piece are two pieces of channel steel which are buckled with each other but are not contacted, wherein two side wing plates of upper channel steel and lower channel steel are all fixed on the outer sides of a front channel steel wing plate and a rear channel steel wing plate, and the non-contacting portion between the upper channel steel wing plates and the lower channel steel wing plates forms a hoping groove. The ultrathin-wall steel structure connecting piece is simple and quick in operation, high in strength, good in axial constraint performance and strong in integrity, effectively controls local buckling of ends when ultrathin-wall section