Because of the moisture evaporation and the varied temperature, the pavement and its semi-rigid base layer are easy to crack in the course of construction and use. This paper studies the stress state near the crack and stability of the crack under traffic loads after the pavement cracks by means of three-dimensional photoelastic model test, the result presented in this paper makes it clear that if in the base layer exists crack, it is possible for crack to be originally refleted to the pavement along the direction of cracks direction. In order to prevent the reflection crack, it is effective t...