In order to explore the water content redistribution and density change in the frost heave process, four samples under different top cold temperature were performed based on the one-dimensional freezing experiment in an open system. The water contents, Computed Tomography (CT) scanning pictures and dry density in different height of the samples were analyzed. The results showed that the frost heave amounts of the samples were controlled by the water absorbed process and the redistribution of the water content from the unfrozen to frozen zone. After the tests, the dry density increased in unfrozen and decreased in frozen zone, which had the opposite law with the water content change.