This investigation focuses on influence of ultra low temperature on frost resistance of cementitious material by freeze thaw cycles test in which liquid nitrogen was applied as ambient medium. The appearance

mass and strength change before freeze thaw recycle and after were measured

respectively. Micro structure of cementitious material before and after freeze thaw recycle was tested by using scan electron microscope (SEM). It is found that

under the condition of ultra low temperature

frost resistance of concrete is better than that of mortar. And the frost resistance of concrete increased with the improvement of concrete strength. The SEM results reveal the structure defect is produced clearly when specimen freeze in liquid nitrogen and thawed in water. It is concluded that freeze thaw recycle with ultra Low temperature is an effective quick method to evaluate the frost resistance of cementitious material because destroying progress was accelerated and experimental time was redned.