Abstract: The protective performance of glass fiber reinforced aerogel was studied preliminarily on an improved spilt Hopkinson pressure bar. High speed photography was used to study the protective mechanism of aerogel. Anti-bullet property of aerogel/steel target was investigated by target experiments. Results showed that after incident pulse shaping using aerogel with a thickness of 12mm, the shape of the stress-time curve on the incident bar changed from rectangle to triangle, the highest stress on the incident bar decreased from 700MPa to 311MPa, the duration time of the pulse increased from 80μs to 210μs. Aerogel burst and consumed a lot of energy when it was impacted by bullet, the stress state of aerogel was also changed. Fiber could postpone the burst process of aerogel and was beneficial to consuming energy. Aerogel/steel target had excellent anti-bullet property. Aerogel could protect the steel target effectively.