Abstract: The structure and performance of steam-cured fly-ash aerated concrete with light weight aggregate prepared by adding light weight aggregate‚air-entraining agent and gas-forming agent‚finely ground aggregate were studied by SEM and other testing methods．The results show that the pore structure was improved．The aperture was less than0． 6mm‚and most of the pore size distributed in the range of0．2～0．5mm．When the density‚volume mixed ratio and strength of light weight aggregate and paste matched with each other‚light weight aggregate could disperse evenly in the sample and formed an intense boundary surface with the paste．As the volume fraction of light weight aggregate increased from 30％ to 45％‚the dry shrinkage decreased significantly‚and the coefficient of carbonization lowed down．Performance such as compressive strength‚dry-shrin-kage and carbonization-resistance of the sample cured at 95℃ for one day could meet the requirements of standard GB／T11968—1997which is the standard of autoclaved aerated concrete． 

Key words: steam-cured, light weight aggregate, fly-ash, aerated concrete, structure, performance