The ultra-light siliceous refractories were prepared by foaming method firing at 1 400 ℃ for 4 hours.The influences of the amount of water added,the amount of waste silica brick powder added and the stirring time on the porosity,bulk density,cold crushing strength and thermal conductivity of the sample were explored.The results show that as the amount of water added increases,the porosity of the sample increases while the bulk density,cold crushing strength and thermal conductivity decrease.The performance is better when the added amount is 50%,which will adversely affect the structure of the sample when too much is added.As the amount of waste silica brick powder added increases,the porosity of the sample increases while the bulk density,the cold crushing strength,and the thermal conductivity decrease,when the added amount is 30%,the porosity is the highest,the bulk density,the cold crushing strength and the thermal conductivity are the lowest.As the stirring time increases,the bulk density of the sample decreases,and the porosity increases.When the stirring time is 15 min,the bulk density of the sample is the lowest,the porosity is the largest,the cold crushing strength is the highest,the thermal conductivity is the lowest,the number of pores is large,and the pore size is uniform,and the distrbution is uniform in the sample.