The present invention discloses a television backlight driving device and the driving method thereof, the said television backlight driving device comprises: an AC-DC module and an LED driving module; when a power is on, the said AC-DC module transforms an input supplied AC power into a DC power before supplying to the backlight LED lightstrip; comparing to the existing backlight driving methods, there is no second process of DC-DC needed, saving a system cost of the power, and improving an efficiency of the system; when the LED driving module determines the detection current larger than the preset current but smaller than the first threshold, a constant-current output for LED current is controlled by adjusting the duty ratio; when the detection current is larger than the first threshold or smaller than the preset current, the LED driving module feeds back the detection current to the AC-DC module; the AC-DC module then controls the DC voltage according to the detection current; different methods for adjustment may save a power consumption, as well as achieving an effect of stabling the current output; it owns a simple circuit structure, and a high system reliability.