The present invention mainly relates to a backlight module for use in a liquid display device. The backlight module comprises a plurality of lamps located above a reflecting plate. Each lamp comprises two ends while each end comprises an electrode. Voltage required for the lamps is provided by at least one circuit board located at least one of two sides of the reflecting plate; wherein the electrodes electrically connect to the at least one circuit board directly. Sizes of the backlight can be reduced in the present invention. Furthermore, costs of material and manufacturing are also reduced.