This study prepared zinc-aluminum hydrotalcite (ZnAl-LDH) by co-precipitation method. The structure was characterized by x-ray diffractometer, fourier infrared spectrometer and scanning electron microscope. The results showed that: ZnAl-LDH is a flake material with size between 100 nm~400 nm. In this paper, ZnAl-LDH with 2% chrome tanning agent was used in leather tanning process. The effects of ZnAl-LDH metal ion ratio and aging time on shrinkage temperature and chromium content in waste liquor were investigated. The application results show that when the molar ratio of Zn2 to Al3 is 2:1 and the aging time is 6h, the Ts of leather could be increased from 74.2 ℃ to 94.1 ℃, and the chromium content in the waste liquor can be reduced from 93.64 mg / L to 46.98 mg / L, the BOD5/CODCr of the waste liquor could be significantly reduced when ZnAl LDH was added.