The present invention relates to an aluminum base alloy with high thermal conductivity, and more particularly, to an alloy for die casting that does not become brittle and has high thermal conductivity, so as to be easily used for LED lighting parts, and contains 0.2 to 2.0 wt % of Mg, 0.1 to 0.3 wt % of Fe, 0.1 to 1.0 wt % of Co, with the remainder being Al.