Using the differential thermal analysis the author has studied the melting parameters (heat of fusion, melting point) of Al powders with different dispersity. It was shown that while reducing Al particle size from micron (coarse industrial powders ASD-1, ASD-4) to submicron and nanosized range (electro-explosive powders, dav=120 nm) the melting point value decreases by six degrees and heat of fusion decreases by 55 % relative to bulk aluminum. Based on the data on the composition and structure of the samples tested it has been ascertained that melting point fall is caused by formation of eutectic system Al-Fe with iron impurities (0,1…0,3 wt. %). The decrease of specific heat of fusion at growth of Al powder dispersity is conditioned by reduction of metal component in submicron and nanoparticles owing to the influence of surface oxide-hydroxide films.