Abstract：The accelerated freez-thawing tests for researching of recycle aggregate concrete have been down and the rezults show that the strength, mass and relative dynamic modulus of recycle concrete are all decreased in different levels with the increasing of freez-thawing cycle numbers. However, the docreasing quantities of mass and dynamic modulus for recycle aggregate concrete are less than that of odinary concrete, but the decreasing quantities of strength is larger than ordinary concrete. And based on the test rezutls a formula for describing the declining of flexural strength of R.A.C. by freezing and thawing is build up and a model for predicting the live-span of R.A.C. in proper srvice is put forward.