In order to investigate the inhibitory effect of geogrid on the dry shrinkage cracking of loess and its engineering application to loess subgrade, the surface crack development of loess samples with and without geogrid under different evaporation temperatures and different sample thickness was qualitatively described and quantitatively analyzed. The results show that the geogrid has obvious inhibitory effect on the development of the cracks in the process of water evaporation. The occurrence and development of the dry shrinkage cracks of the loess samples can be divided into three stages, namely the formation stage, the acceleration stage and the stabilization stage. The ε defined in this paper is the ratio of the number of cracks to the number of crack nodes, it can reflect the penetration depth of the crack, the smaller the value, the deeper the penetration. Geogrid has obvious inhibitory effect on the penetration of dry shrinkage cracks, and can effectively slow the development speed of cracks and diffuse the internal shrinkage stress of the loess samples. This provides a new idea for treating the dry shrinkage of the subgrade in loess area.