Cage-type octavinyloctasilsesquioxane (POSS-Vi), acrylamide (AM) and methacrylic acid (MAA) were used as raw materials to prepare amino and carboxyl POSS/polymer composites (P (POSS-AM-MAA)) by free radical polymerization. The structure and morphology of P (POSS-AM-MAA) were characterized by Fourier transform infrared spectroscopy, X-ray diffractometer, and transmission electron microscope. The results showed that: POSS/polymer composites were prepared, and the POSS cage structure was covered by polymer segments. P (POSS-AM-MAA) combined with 4% glutaraldehyde was used in the tanning process of pickled goat skin, and the influence of amino content, molecular weight and composite material dosage on the properties of leather was investigated. The results showed that the shrinkage temperature of the tanned leather was 83.7 ℃, and the thickening rate was 109.5% , which were both higher than glutaraldehyde tanned leather, when the amino content was 433μmol/g, the number-average molecular weight of P (POSS-AM-MAA) was 27237, and the amount of P (POSS-AM-MAA) was 8% of the weight of pickled goat skin.The free formaldehyde content in crust leather was 28.3 mg/kg. The tensile strength, elongation at break and the tear strength of combined tanned leather sample was 16.5 MPa, 109.5%, and 58.8 N/mm,which was similar to glutaraldehyde tanned leather.