In this study, zinc and aluminum powders were used as foaming agents and organosilane was innovatively used as a modifier to synthesize a chemically foamed geopolymer used as lightweighted, porous wall. With increasing the amounts of zinc or aluminum powders, thermal conductivity and compressive strength were decreased. Zinc powders accompanied with organosilane made the foamed geoplymer with uniform pore size distribution, which reduced thermal conductivity to 0.113W/m.K, and proper compressive strength about 36.67 kgf/cm2. The produced foamed geopolymer with enhanced compressive strength and low thermal conductivity is an ideal material for fire protection, sound absorption and thermal insulation.