An exemplary backlight module includes a light source, a light guide panel, and a frame. The light source includes a substrate, blocks disposed on the substrate and spaced from each other, and light emitting diodes (LEDs) each including a first electrode, a second electrode, a chip and a bonding wire. The first and second electrodes are arranged on the substrate between two blocks, and are electrically connected to each other via the chip and the bonding wire. The light guide panel transforms linear light to planar light. The frame receives the light source. Each of two adjacent corners of the frame are step-shaped or wedge-shaped, with two ends of the light source correspondingly cut into step or wedge shapes to engage the frame.