Disclosed is a junction box limiting device. The junction box limiting device comprises a box body limiting base (1), a fixed base plate (2), a wiring harness limiting base (3) and a wiring harness press plate (4), wherein the box body limiting base (1) and the wiring harness limiting base (3) are both fixedly arranged on the fixed base plate (2) in a parallel manner, and the wiring harness press plate (4) is movably connected to the wiring harness limiting base (3). The positioning device has a simple structure, is easy to operate, is applicable to a variety of junction boxes and assemblies of different sizes and has a good compatibility, and makes the limiting easy, quick and accurate especially for the positioning of a junction box during the manufacturing of a flexible photovoltaic assembly.