A new effect of aging time (AT) on the shrinkage of ordered mesoporous carbon (OMC) prepared by an evaporation-induced triconstituent co-assembly method has been reported. Increasing AT from 0.5 to 2.0 h can gradually reduce framework shrinkage of the OMC during carbonization. This novel effect is effective and simple for preparing the OMC with large mesopore sizes, high pore volumes and surface area.