The invention discloses a porous geopolymer/aerogel heat insulation composite. The porous geopolymer/aerogel heat insulation composite comprises a porous geopolymer and silica aerogel, wherein the porous geopolymer is a matrix, and the silica aerogel is embedded into pores of the porous geopolymer as filling bodies to form the porous geopolymer/aerogel heat insulation composite. The invention also discloses a preparation method of the porous geopolymer/aerogel heat insulation composite, wherein a physical foaming method is adopted for preparing the porous geopolymer and the porous geopolymer/aerogel heat insulation composite is prepared by adopting a sol-moistening-gel technology. The porous geopolymer/aerogel heat insulation composite gives consideration to the advantages of high strength, high temperature resistance, low volume weight, low thermal conductivity and good waterproofness, the performance requirement of the actual application on a heat insulation material is met, consumption of a solvent and a modifier is low in a preparation process, process is easy to control, and continuous production can be realized.