The accelerated carbonation tests and repeated loading tests on C20 and C30 concrete specimens were carried out to investigate the effect of carbonation on the mechanical properties of concrete under repeated loading. Test results show that with the increase of carbonation depth, the brittle failure of concrete became more significant, the elastic modulus and the compressive strength increased, the strain at peak compressive stress decreased, respectively. The common point curve deviated farther from the envelop curve, the shape of the descending branch of envelop curve became much steeper, the concave shape of the unload curve became more and more obviously, the shape of reload curve became more and more gentle, the hysteresis of strain recovery for carbonated concrete became more obviously. Based on regression analysis of test result, the analytical stress-strain response of carbonated concrete subjected to repeated loading were established.