A connecting structure of a bed frame is provided. The bed frame includes a frame, bed legs, and a bed plank support frame. Two side boards of the frame are provided with a plurality of support portions, respectively. One end of each of a plurality of support members of the bed plank support frame is connected to a corresponding one of the support portions of the side boards. Another end of each of the plurality of support members is connected to a corresponding one of support boards of the connecting spine. The connecting spine is designed as a -shaped structure, and the upright board is integrally formed with the support boards so that one end of each of the plurality of support members can be directly attached to the corresponding support board of the connecting spine, providing a simple structure and a stable support.