A driving method for a backlight module and a display device are disclosed. The driving method includes: generating mapping information from each local dimming area to the corresponding piece of local area dimming data according to preset positional relationships between a backlight driving chip and lamp beads in the backlight module; receiving, by a timing control chip, a frame of display data, and converting the display data into panel driving data and corresponding multiple pieces of local area dimming data; receiving, by a backlight driving circuit, the multiple pieces of local area dimming data in sequence, turning on the channel corresponding to the current local dimming area in turn according to the mapping information, and driving the lamp beads in the current local dimming area.