The present invention discloses a backlight module and a liquid crystal display (LCD) using the same, which can achieve local dimming. The backlight module includes a light guide plate (LGP), which has a groove formed on a bottom. A cross-section of the groove can be arc-shaped. The backlight module further has a plurality of light sources disposed under the LGP at positions corresponding to the groove. The light sources can be two LED light bars. Light emitted from the light bars enters into the LGP and radiates from the LGP. The present invention does not require so many light sources, and thereby power consumption is reduced. The light sources are disposed under the LGP, so that heat can be dissipated through a back plate of the LCD.