Abstract: The concrete deteriorated by freezing-thawing effect is tested under cyclic loading and unloading at different strain rates. The characteristics of the outer envelope line for strain-stress curves are analyzed. The dissipated energy, elastic strain energy and plastic strain energy are defined, and the relationship between each kind and the freeze-thaw cycles or the loading and unloading cycles is studied. It turns out that the outer envelope line rises at first and then drop down as a whole; the peak stress decreases but the peak strain increases gradually with the increase of freeze-thaw cycles; the strain rates have no effects on the shape of the outer envelope line; the strain-rate sensitivity for concrete is influenced by the freeze-thaw cycles; the dissipated energy, elastic strain energy and plastic strain energy increase at first and then drop down with the increase of loading and unloading cycles; the brittleness of concrete is weakened by freeze-thaw cycles; about 90% energy coming from the work of external force is used in irreversible process.