To enhance the mechanical properties of HTPB four-composite solid propellants, 3-[2-(2-aminoethylamino)ethylamino]propyl-trimethoxysilane (A1130) and ureidopropyltriethoxysilane (A1160) were employed to modify the surface of HMX and qy-HMX, followed by their application in solid propellant formulation. Scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM) and thermal analysis (DSC-TG) were used to test the morphology, structure and performance of the samples. The interfacial enhancement effects were systematically investigated using an electronic universal testing machine and dynamic thermomechanical analyzer (DMA) to assess mechanical properties and adhesion characteristics. Results demonstrate that silane treatment forms continuous coating layers without changing the crystalline structure. Silane coating inhibits effectively the transformation of HMX, increasing the phase transition temperature of HMX@A1130 and HMX@A1160 to 193.9 ℃ and 201.4 ℃, which are 2.3 ℃ and 9.8 ℃ higher than that of raw HMX. The mechanical tests reveal significant improvements in propellant tensile strength across both high temperature (70 ℃) and low temperature (-50 ℃) conditions. Notably, A1130-modified propellant exhibits enhanced tensile strength at -50 ℃/500 mm·min-1, with the adhesion index reduced from 1.52 to 1.24 at -50 ℃/500 mm·min-1. Under -50 ℃/10 mm·min-1, the tensile strength of propellants modified with HMX@A1130 and HMX@A1160 increasing by 29.9% and 31.6%, and the maximum elongation increased by 29.9% and 31.6%, respectively. DMA results show that the peak value of loss factor for the A1130-modified propellant decreased from 0.51 to 0.47, indicating a mitigation of the interfacial ‘dewetting’ phenomenon at low temperatures. The fracture surface morphology analysis results are in good agreement with the tensile test and DMA test. It shows that the addition of two silane coupling agents has a significant interfacial modification effect, and A11330 can inhibit the interfacial ‘dewetting’ on hydroxyl-terminated polybutadiene system.