In 2001, a large number of ivory artifacts were unearthed during the excavation of the Jinsha Site. To prevent water loss, the ivories were preserved by silicone sealing. Short-term water loss experiments showed that silicone sealing effectively reduced water loss in the ivories. Ivory artifacts have been sealed and preserved for more than 20 years. This study aimed to evaluate the long-term effects of silicone sealing on the ivories. The external features, chemical composition, crystal structure, pore structure and moisture characteristics of the silicon-sealed ivories were analyzed using ultra-depth video microscopy, X-ray photoelectron spectroscopy, nitrogen adsorption, low-field nuclear magnetic resonance, dynamic moisture adsorption, thermogravimetric analysis and differential scanning calorimetry. The testing results were then compared with those of freshly unearthed Jinsha Site ivories, ivories unearthed from the Sanxingdui site, and modern ivories in terms of appearance, chemical composition, crystal structure, pore structure and moisture characteristics, to comprehensively assess the preservation effect of silicone sealing. The results show that silicone has provided effective protection, as the ivories have no signs of collapse or deformation. The silicon-sealed Jinsha ivories remain primarily composed of hydroxyapatite, with a crystal size of about 28 nm, and the organic matter has largely degraded. The overall composition and crystal size of ivories are similar to those prior to sealing. However, a small amount of silicone, invisible to the naked eye or under optical microscope, were found on both the surface and interior of ivories, with surface contamination being slightly more pronounced. The pore structure consists mainly of mesopores (2-50 nm), along with a few micro-and macropores (<1 000 nm), with an average pore size of about 15 nm. Silicone sealing has not increased the pore size or porosity of the ivories and demonstrates good moisture retention. The average moisture content of the ivories after over 20 years of silicone sealing remains around 38%, indicating that long-term silicone sealing effectively maintains the moisture stability of ivories.