Abstract：Mesoporous molecular sieves SBA-15 were synthesized by conventional hydrothermal process using tetraethylorthosilicate (TEOS) as silicon source and triblock copolymer P123 as template. Ag/SBA-15 was fabricated in AgNO3 or [Ag(NH3)2]NO3 solutions as the metal source after the inner and outer wall of SBA-15 were modified with functional molecules. The morphology of synthesized composite was characterized by transmission electron microscopy (TEM). The results showed that monodisperse Ag nanoparticles and nanorods were formed in the channel of SBA-15 respectively. Reasonable surface enhanced Raman scattering (SERS) activities of Ag/SBA-15 composite were observed by using thiophenol (TP) as the probe molecules. Besides, the Ag/SBA-15 composite exhibited high catalytic activities for the reduction of p-nitrophenol in the presence of NaBH4. By using the real time SERS measurements, the mechanism of the catalytic reduction of p-nitrophenol was proposed.