Square pipe connecting piece

A square pipe connecting piece is symmetrically and fixedly connected to the two sides of a first square pipe and a second square pipe which are connected and comprises a rectangular connecting piece body, one end of the connecting piece body is folded upwards to form a buckling part, and the two sides of the end, away from the buckling part, of the connecting piece body are folded upwards to form a pair of symmetrical reinforcing parts. At least four mounting holes are formed in the connecting piece body in an array mode. During installation, the first square pipe and the second square pipe abut against each other at 90 degrees, the connecting pieces are connected to the first square pipe and the second square pipe in a buckled mode, the connecting pieces are fixedly connected to the first square pipe and the second square pipe through bolts penetrating through the installation holes, and connection is completed. Wherein the first square pipe abuts against the connecting piece body and the inner wall of the