Abstract: Thermal neutron scattering of SiO₂ may have the impact on analysis of the geologic storage of nuclear waste and criticality safety of space reactor’s falling accident. The ACE format SiO₂ thermal neutron cross sections were generated by using the new TSL library of ENDF/B Ⅶ-1. Cross sections at different temperatures were investigated. Comparison of SiO₂ thermal neutron scattering cross sections between phonon model and free gas model was done. The space reactor’s criticality safety in wet sand was analyzed by using the new library, and the harmful moderating proportion of wet sand was given.