Abstract: In our report, in order to analyze the effects of polymer cement ratio, water binder ratio, and water reducing agent content on the performance of polymer modified interface agent（water retention, bond strength, impermeability） of aerated concrete block, and the macro performance was determined, and the variance and range analysis were performed, and the micro morphology（ESEM） was determined. The results showed that the polymer cement ratio is the most important factor affecting the water retention, bond strength and impermeability of the interfacial agent. With the increase of polymer cement ratio, water retention, 7 d and 14 d shear bond strength, and 7 d impermeability pressure increased. When the three component copolymer PTB emulsion was added, a large number of micropores were formed inside the mortar, forming a continuous space skeleton matrix network structure, which had better physical and mechanical properties, and improved the water holding capacity, bond strength and impermeability of the interface agent. Our findings can provide a theoretical reference for improving the performance of interface agent for aerated concrete block.