Abstract: Silane-crosslinked halogen-free flame-retardant polypropylene(PP)/poly(ethylene 1-octene(POE) composites were prepared by a two-step melt extrusion method using magnesium hydroxide(MH) and aluminum hydroxide（ATH）as flame retardants. The graft ratio of silane, mechanical properties, thermal performance and flame retardancy of the resulting compounds were extensively investigated. The results indicated that the compounds achieved a creep elongation lower than 25 % and an eternal deformation ratio lower than 4 % at the PP/POE/MH/ATH/silane weight ratio of 50/50/95~47.5/0~47.5/3. The limiting oxygen index of the compounds was improved slightly with increasing ATH content at a fixed content of the flame retardants. The compounds containing MH exhibited a higher thermal stability than those containing MH and ATH. The decreasing smoke release rate was also found to show a variation trend in an order of PP/POE/ATH compounds>PP/POE/MH/ATH compounds>PP/POE/MH compounds.