A apparatus and a method for reducing power consumption of a LCD (Liquid Crystal Display) backlight lamp includes a power unit supplying power, a control unit being supplied power from the power unit and outputting a brightness control information signal by incremental levels, a key input unit having adjustment keys for adjusting a brightness of a LCD screen, a memory unit storing a control information signal inputted from the control unit, an inverter unit being inputted the brightness control information signal by levels from the control unit and outputting power of a backlight lamp by corresponding incremental levels, and a backlight lamp being driven by the power output from the inverter unit. The apparatus and method are capable of reducing unnecessary power consumption by increasing the power to drive the backlight lamp gradually so as to be similar to an actual brightness increase curve of a backlight lamp in the consideration of luminescent characteristics of the backlight lamp and then supplying a constant preset power level after finishing a starting operation of the backlight lamp.