In order to enhance the mechanical properties of silica aerogel,the silane coupling agent KH550 and KH560 were modified to grafted glass fibers in two steps,and then fiber reinforced silica aerogel were prepared.Scanning electron microscope,infrared spectrometer,specific surface and aperture distribution instrument,TG-DTA analyzer,thermal conductivity instrument and electronic dynamic and static fatigue testing machine were used to characterize the fiber reinforced silica aerogel.The results showed that after the glass fiber reinforced silica aerogel modified by silane coupling agent compounded with silica aerogel,the network structure was more uniform,the framework strength was more stable,the pore diameter was less than 30 nm,and the thermal stability was better.At the same time,the optimal addition amount of modified glass fiber was 20%（mass fraction）.At this time,the density was 0.167 g/cm³,the thermal conductivity coefficient was 0.018 5 W/（m·K）,the contact angle was 127°,the bending strength was 1.042 MPa and the compressive strength was 0.669 MPa.The expected purpose of the experiment was achieved.