In cold regions, recurrent freeze–thaw action and loading conditions are important factors affecting the long-term durability of natural rocks in engineering systems. This study explores the effects of freeze-thaw action and strain rate on the mechanical behavior of the sandstone retrieved from Urumqi areas of western China. In addition, a decay function model was built for predicting the mechanical degradation and durability of the tested rock based on the P-wave velocity results. The results suggest that the mechanical properties of samples under either static or dynamic loading decrease with the increase in freeze-thaw action. However, the enhancement influence of the strain rate on dynamic compression strength and deformation modulus under freeze-thaw action still exists and increases with the increasing strain rate. Moreover, under the same dynamic loading, increasing in freeze-thaw action can aggravate the fragmentation degree of the tested sample. The proposed decay model is in good agreement with the data measured in the tests, and the model can accurately describe the influences of freeze-thaw action and strain rate on deterioration responses of the rock. Thus, this decay model can be used to obtain better predictions of the long-term durability of tested rocks under the effect of freeze–thaw action and strain rate.