Dense γ-Y2Si2O7 ceramics are promising silicates with very low thermal conductivity and excellent chemical and thermal stability in harsh environments.However,preparation and properties of porous γ-Y2Si2O7 were rarely reported.In this work,we successfully fabricate porous γ-Y2Si2O7 with multiple pore structures by in situ foam-gelcasting/reaction sintering method using Y2O3 and SiO2 powders as starting materials.