100mm diameter split Hopkinson pressure bar (SHPB) was used to take impact testing on red sandstone specimen of different freeze－thaw cycles in the paper. The dynamic properties of red sandstone, including stress－strain curves and variations of peak stress, peak strain and elastic modulus, were researched. The effects of red sandstone caused by freeze-thaw cycles were tested by ultrasonic detector and scanning electron microscopy. The results show that with the increase of number of freeze-thaw cycle, peak stress reduces, and peak stress presents strain rate effect significantly. Using peak stress relative loss   to take identify research of specimen under different strain rates,   is approximately linear with the freeze-thaw cycle. What’s more, with increasing number of freeze-thaw cycle, peak strain gradually increases, and elastic modulus of specimens decreases. Scanning freeze-thaw cycle’s specimens using scanning electron microscopy finds that, after freeze-thaw the cementation material of specimens of red sandstone falls off largely, and the coupling between the particles decreases. Quantitative analysis shows that, the increase of porosity area and reduce of strength of red sandstone have obvious correlation.