The present invention provides a backlight module, which includes a backplane, a backlight source arranged inside the backplane, a reflector plate arranged inside the backplane, a light guide plate arranged on the reflector plate, and a mold frame mounted to the backplane. The backplane forms a pawl section. The mold frame forms a retention slot corresponding to the pawl section. The pawl section is receivable in and retained by the retention slot so as to fix the mold frame to the backplane. The backlight module uses a pawl section formed on the backplane and a retention slot formed on the mold frame to engage the pawl section so as to mount the mold frame to the backplane through snap-fitting connection thereby showing a simple structure, being easy to assemble and disassemble, effectively saving time, and thus controlling the cost.