Geopolymerization is a complicated process.Even in a simple system consisting of an alkaline activator, such as water glass, and a silicate-aluminate material, such as fly ash, setting time and mechanical strength development of geopolymerized product strongly depend on water glass modulus and solid content, fly ashs fundamental properties, and their weight ratio (liquid to solid ratio, L/S ratio).This paper presented the effects of solid content and modulus of water glass and its ratio to a given fly ash on setting time and mechanical strength of fly ash-based geopolymer.With given water glass and its L/S ratio, the effects of fundamental properties of fly ash,such as particle size (D50) and chemical compositions (Si/A1 ratio and %CaO), were studied.With given water glass and fly ash, the effects of key parameters to foam geopoloymer using hydrogen peroxide were also studied.Finally, fly ash-based geopolymer foam panels were developed for thermal insulation and fire protection applications.Our foamed product (0.057 W/m/K, 201 kg/m3, 1.27 MPa) as a new "green" environmental friendly material class met the key requirements of the China Industry standard JC/T 2200-2013 foam Type II requirements and exceeded the existing foamed cement performance (0.065 W/m/K, 220 kg/m3, <0.5 MPa) for external wall thermal insulation applications, and gypsum foam for fire protection applications.