Owing to common plaster for aerated concrete with bad water retention, low bond strength,easy cracking and bulging,the influence of polymer powders on the performance of plaster for aerated concrete was researched and its mechanism of influence was discussed.The result indicates that putting hydroxyethyl methyl cellulose and polyethylene vinyl acetate redisper-(sible) emulsion powders into mortar simultaneously can greatly improve the water retention of mortar,raise the workability,and increase the bond strength.The problems of cracking,bulging and slough,when common plaster is used for aerated concrete,can be well solved.