The present disclosure provides a housing structure of a backlight module, a backlight module and a display device. The housing structure of a backlight module includes a back plate and a plastic frame. The back plate includes a bottom plate, a first sidewall extending perpendicularly from one side of the bottom plate, and a first engaging portion disposed on the first sidewall. The plastic frame includes a second sidewall, a slot disposed on the second sidewall, and a second engaging portion disposed on a side surface of the slot. The slot is elastically deformable by a force. The first sidewall can be clamped in the slot. The first engaging portion can be engaged with the second engaging portion.