Abstract: A micro-CT is used to monitor the freeze-drying processes of pig arteries which are pre-cooling at different rate.Imagines are analyzed by grey scale value evaluation.The pre-cooling rate are 0.5 ℃ ·min^-1,1 ℃· min^-1,2 ℃· min^-1 result the variation ratio of the porosity 11.9%,16.6%,29.7% respectively and the gray scale value 2.27%,3.64% and 6.36% respectively.At the same time,the movement of sublimation interface is also scanned,and the characteristics of the movement are discussed from the views of the vessel's inner composition.