Abstract: The preparation of ZnAl Layered Double Hydroxide [ZnAl-LDH] was studied. ZnAl-LDH was synthesized by the methods of variable and constant pH respectively
with the materials of Zn(NO₃)₂, Al(NO₃)₃, NaOH. The effects of each factor on preparation of LDH were disscused systematically by XRD and TG--TDA
data. It was showed that single LDH with high crystallinity can be prepared at the test conditions without N₂ gas protection. 80℃, 2h reflux treatment can
be replaced by 115℃, 2h hydrothermal treatment. Zn/Al ratio veries with different pH values. The amount of water localized in the interlayers is related to Zn/Al ratio. Among the
factors, pH value is the most effective.

Key words: layered compound, double hydroxide, anionic clay, prepratio