A bed frame includes a frame, bed legs, and a bed plank support frame. The frame includes two side boards, a head board, and a tail board. Respective bottoms of opposing sides of the two side boards are provided with a plurality of U-shaped connecting members, respectively. The bed plank support frame includes a plurality of support members. Two ends of each support member are connected to U-shaped connecting grooves of the corresponding U-shaped connecting members of the two side boards, respectively. The bed plank support frame is sunk when in use. After a bed plank is placed, there is a certain distance between the bed plank and the top of the frame, so that the frame can form four stop sides. After a mattress is placed on the bed frame, the mattress is restrained in the frame, not sliding.