A serious of spherical Co-MCM-41s with different cobalt content was synthesized and characterized by XRD, SEM, N2 isotherms and ICP techniques. The influences of synthesis conditions on the structure were also studied. The use of ascorbic acid as reductant had significant influence on the morphology and the catalytic activity of Co-MCM-41. The prepared samples exhibited higher catalytic activity in the direct hydroxylation of benzene by H2O2 than those with common morphology.