Abstract: To explore slag-based geopolymer porous material under the condition of different porosity, pore diameter distribution of performance and improve the mechanism of water absorption, the experiments on the water absorption, water release properties of the slag-bnsed geopolymer were Conducted, with blast furnace slag, fly ash, and sodium silicate as the main raw material, and hydrogen peroxide as foaming agent, Image analysis softwares and the fractal theory were adopted to analyze its microstructure and pore structure fractal characteristics.The results show that the porosity, maximum pore size and water absorption of the porous material increase with the increase of the foaming agent, while the time needed to release water per unit mass and fractal dimension of the pore surface decrease.When the dosage of foaming agent is 1.6 ml, the water absorption rate of the material reaches 62 %, and the time required to release water per unit mass is only 1.38 h.At this point, both water absorption and water release properties of the material are taken into account.