Disclosed herein is an LED backlight module, which includes a metallic plate, a metallic sidewall, a connecting portion, a light guide and an LED ribbon. The metallic sidewall is substantially perpendicular to the metallic plate and located beside a side edge of the metallic plate. The metallic side-plate has a lower edge extending downwards to a position beneath a lower surface of the metallic plate. The connecting portion extends in a direction towards the side edge of the metallic plate from the lower edge of the metallic sidewall, and is further connected to the side edge of the metallic plate. The light guide is disposed above the metallic plate, and the LED ribbon for emitting a light into the light guide is disposed on the metallic sidewall.