Abstract: <em<σ-</em<ε relations of float glass and tempered glass have been studied with the split Hopkinson press bar (SHPB). Low velocity impacts were carried out by SHPB. Experimental results show that the impact properties of float glass are consistent with the properties of ceramics, while the impact properties of tempered glass behave as plastic yield besides elastic properties. Fragmentation forms of tempered glass are grainy, while float glass are powdery. The results show that the impact properties of float glass have been greatly improved after the air chilling.