One series of self compacting concrete(SCC) specimens incorporating fly ash and two series of SCC specimens incorporating both fly ash and ground granulated blast slag were designed. Based on accelerated carbonation and water absorption test, the effects of cement replacement by only fly ash and by both fly ash and slag powder on the carbonation resistance of SCC were studied. It is found that, when the replacement rate of fly ash is more than 40%(by mass), the carbonation depth of SCC increases rapidly as the replacement rate increases. However, replacement by both fly ash and slag powder greatly improves the carbonation resistance of SCC incorporating massive fly ash. Both positive and negative effects caused by mineral admixtures on carbonation resistance of SCC are analyzed.