Multi-carboxyl P(POSS-MAA) composite material was prepared by the free radical polymerization of methacrylic acid (MAA) and Octavinyloctasilsesquioxane (POSS-Vi) which was obtained by vinyl trimethoxysilane(A-171) of hydrolysis and condensation. The structure of the polymer was characterized by Nuclear Magnetic Resonance(NMR), Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD) and Transmission Electron Microscope(TEM), the results showed that P(POSS-MAA) composite was successfully obtained, and the POSS-Vi in P(POSS-MAA) composite can be uniformly dispersed. It was indicated that the shrinkage temperature and thickening rate of the leather had improved, in addition, the chromium content in the waste solution was also decrease when the P(POSS-MAA) composite combined with mass fraction 2% chromium was applied to the tanning process of goat acid skin. Meanwhile, when the content of the POSS-Vi was 6% in the P(POSS-MAA) composite, the shrinkage temperature ( Ts ) can reach up to 96.5℃ and thickening rate can also increased to 36% after the leather pretanned with the P(POSS-MAA) composite combined with 2% chromium , and the chromium mass concentration in the waste solution can be decreased from 122mg/L to 41mg/L compared with chrome tanning.