The present invention provides a composite that consists essentially of a mesoporous silica substrates and silver nanoparticles. In particular, the mesoporous silica substrate comprises a mesoporous silica thin film with perpendicular nanochannels and mesoporous silica nanoparticles with perpendicular nanochannels and the silver nanoparticles non-covalently bond onto surface of the mesoporous silica substrate and have a distribution density of 107-1013 number/cm2 on the surface. The preparing method and antibacterial application of the composite are also disclosed in the present invention.
