Mesoporous silica nanospheres (MPNSs) were synthesized by the sol-gel method and were investigated by X-ray diffraction, nitrogen sorption, and transmission electron microscopy. The analyses showed that the MPNSs were highly dispersed, with a diameter range of 50-250 nm. Further, the polycation poly(allylamine hydrochloride) was coated on silica MPNSs to form a positively charged surface and to facilitate the loading of DNA molecules. The composite was successfully used as a intercellular carrier of DNA molecules, and this was confirmed by agarose gel electrophoresis and confocal laser scanning microscopy. Evidently, this composite has potential to be used as a carrier for a DNA delivery system.