The paper uses the terminal carboxyl groups of hyperbranched polymer complexing the Al3+ in aluminum sulphate synthesis a new chrome-free tanning agent (HPC-Al). Through single-laboratory methods optimize the conditions. The molecular structure of HPC-Al was characterized and analyzed by IR and XRD. The results indicated that the reaction raw ratio was m(HPAE-C)：m(Al2(SO4)3)=2：1, pH was 3, reaction temperature was 30℃, and the time was 3h. Thermal decomposition temperature is 243℃. Application results show that: the shrinkage temperature of HPC-Al tanning leather is 76.6 ℃, The shrinkage temperature greater than 95℃ after chrome retanning，and it has greatly improved leather fullness, softness and physical- mechanical properties.