A silica aerogel (SA)/poly(methyl methacrylate) (PMMA) hybrid composite with a non-covalent interaction phase interface was prepared by introducing γ-aminopropyltriethoxysilane and acrylamide. The effects of the non-covalent interaction phase interface on the performance of SA/PMMA hybrid composites have been investigated by performing scanning electron microscopy, energy-dispersive X-ray spectrometer, Fourier transform infrared spectrometer, nitrogen gas (N2) adsorption–desorption, thermogravimetric analysis, gel permeation chromatograph and mechanical bending strength test. The results indicated that an SA/PMMA hybrid composite with a non-covalent interaction phase interface and a nanoporous structure was obtained. The strong interface bond strength of the non-covalent interaction phase interface between SA phase and polymer phase facilitated the coupling effect for phonon transmission, which could improve the thermal stability and the thermal conductivity of composites. The strong interface bond strength of the non-covalent interaction phase interface also restricted the movement of the molecular chains of the polymer, which could improve the mechanical properties of composites.