A simple hydrothermal approach is used to prepare water-soluble carbon quantum dots (W-CQDs) by using glucose as the precursor and PEO106PPO70PEO106 (F127) as the controlling agent. The homogeneous W-CQDs have an average size of 2.6nm and show well dispersibility. W-CQDs/mesoporous SiO2 composites are synthesized by using mesoporous SiO2 as the carrier. The as-synthesized composites are characterized by SEM, TEM, XRD, and fluorescence spectrometry. The fluorescence intensity and quantum yield of the composite are higher than those of W-CQDs.