The position of gravel soil infiltration peaks plays an important role to the design and safe operation of dam, but it can not be experimentally verified by the previous techniques. CT technology, as the most advanced non-destructive detection technology, has a unique advantage in the rock mechanics experiments. CT technology was applied to the gravel soil infiltration tests, the obtained CT images are clear and reliable. It can accurately indicate the position of infiltration peak, therefore, it ' s an effective approach. From the CT infiltration images we can see the more obvious stratification line, meanwhile peak appears ladder-like, which is the phenomenon caused by capillarity in the development process of the infiltration peak invasion.