A liquid crystal display (LCD) device includes an LCD panel and a backlight module providing a light source to the LCD panel. Because a light emitting diode (LED) is associated with reduced costs, a typical backlight module mainly uses the LED as a light source. The light source is a lightbar formed via a plurality of the LEDs connected in series, and a boost circuit drives the lightbar to emit light. An output end of the LED is connected in series with a metal-oxide-semiconductor field-effect transistor (MOSFET), a constant current chip is used to control switch off the MOSFET, and an effective current flowing through the LED lightbar is controlled via adjusting a duty ratio of the MOSFET, which can dim the LEDs. When one or more LEDs of the LED lightbar are short-circuited, brightness of entire LED lightbar is reduced. However, at this moment, the constant current chip may not switch off current of the LED lightbar, which reduces comfort level for user to watch, and affects the constant current chip and related circuit boards.