An inorganic-organic hybrid fluorescence chemosensor (DA/SBA-15) was prepared by covalent immobilization of a dansylamide derivative into the channels of mesoporous silica material SBA-15 via (3-aminopropyl)triethoxysilane (APTES) groups. The primary hexagonally ordered mesoporous structure of SBA-15 was preserved after the grafting procedure. Fluorescence characterization shows that the obtained inorganic-organic hybrid composite is highly selective and sensitive to Hg(2+) detection, suggesting the possibility for real-time qualitative or quantitative detection of Hg(2+) and the convenience for potential application in toxicology and environmental science.