In order to improve the mechanical properties of SiO2 aerogel-glass fiber composites, effects of different solvents (cyclohexane, n-hexane, ethanol, acetone) and different dispersing modes (planetary ball milling, ultrasonic dispersion and mechanical stirring) and dispersing duration (10-40 min) on the dispersion of chopped alkali-free glass fiber bundles were studied to determine the best dispersion process. On this basis, the materials were batched according to the mass fraction of SiO2 aerogel powder to chopped alkali free glass fiber bundles of 90:10, and a certain amount of zinc oxide light-screening agent and phenolic resin binder were added. SiO2 aerogel glass fiber composite specimens were prepared by direct adding chopped alkali free glass fiber bundles and pre-dispersed chopped alkali free glass fiber bundles, respectively. The cold crushing strength and the thermal conductivity at different surface temperatures (300, 400, 500 and 600 ℃, respectively) of the specimens were measured. The results show that: (1) the optimum dispersion process of chopped alkali-free glass fiber bundles is using ethanol as solvent and mechanical stirring for 30 min; (2) pre-dispersion of chopped alkali-free glass fiber bundles has little effect on the thermal conductivity of SiO2 aerogel-glass fiber composites but can improve the cold crushing strength.