Nanosized Ce-doped silica particles (without and with Al addition) dispersed within pores of mesoporous silica host were synthesized by soaking and sol-gel technique. It was found that the dispersed phosphor particles are mainly located within the pores that are less than 4 nm in diameter. There exist two luminescence peaks at about 350 and 700 nm, respectively, for this phosphor in the dispersed or aggregated state. For the dispersed system, the luminescence intensities of both peaks are more than 14 times higher than those of the aggregated one, the shoulders on the lower sides of the luminescence peaks disappear, and no effect of Al addition on the luminescence occurs which is in contrast to the aggregated system. This is mainly attributed to the high dispersity of nanosized phosphor particles in the host and the effective avoidance of a clustering of Ce3+ ions.