［Objective］To modify moisture-curable polyurethane with silane coupling agents toimprove its thermal resistance for the conservation of cultural relics in humid environments.［Methods］A partially silane-terminated silicone-modified moisture-curable polyurethane was synthesized using polyether polyols（polyethylene glycol and polytetramethylene ether glycol）and aliphatic isocyanates（isophorone diisocyanate） as precursors，with trimethoxy（3-（phenylamino）propyl）silane as the secondary aminosilane coupling agent. The polyurethane films were characterized through chroma meter， UV-Vis spectrophotometry，Fourier-transform infrared spectroscopy（FT-IR）， thermogravimetric analysis（TGA），and thermal-oxidative aging tests to evaluate their appearance，hydrogen bonding degree， and thermal stability.［Results］The results showed that the silicone coupling agent-modified moisture-curable polyurethane films exhibited a visible light transmittance of 85%-89% with a color difference（ΔE）of <0. 4. Increasing the hard segment/soft segment mass ratio enhanced microphase separation， while increasing the dosage of the secondary aminosilane coupling agent reduced it. The activationenergies calculated by the Flynn-Wall-Ozawa（FWO）and Kissinger-Akahira-Sunose（KAS）methods increased from 77. 33-99. 71 kJ/mol to 104. 02-127. 39 kJ/mol before and after silicone modification， showing an increase of 27. 8%-34. 5%. The thermal degradation mechanisms were consistent withdiffusion models（D₁，D₂，and D₃）and the reaction order model（F_n）. The color difference upon heating was reduced.［Conclusion］ The synthesized silicone coupling agent-modified polyurethane is colorless and transparent，exhibits excellent thermal stability，and shows promising potential forapplication in the conservation of fragile organic cultural relics excavated from humid environments.