Mesoporous carbon–Cr2O3 (M-C–Cr2O3) composite was prepared by co-assembly of in situ formed phenolic resin, chromium precursor, and Pluronic block copolymer under acidic conditions, followed by carbonization at 750°C under Argon. The TEM results confirmed that the Cr2O3 nanoparticles, ranging from 10 to 20nm, were well dispersed in the matrix of mesoporous carbon. The composite exhibited an initial reversible capacity of 710mAhg−1 and good cycling stability, which is mainly due to the synergic effects of carbons within the composites, i.e. confining the crystal growth of Cr2O3 during the high temperature treatment step and buffering the volume change of Cr2O3 during the cycling step. This composite material is a promising anode material for lithium ion batteries.