Marine concrete is a necessary basic material for ocean development. However, the service life of marine concrete is adversely affected by microbiologically influenced corrosion (MIC). A new type of Ag/TEOS/IBTS composite emulsion (ATS) which can be coated on the concrete surface to prevent MIC was fabricated, characterized and evaluated. Compared with Ag/TEOS composite emulsion (AT) and Ag/IBTS composite emulsion (AS), ATS has the best hydrophobicity among the three emulsions, with a contact angle of 119.67°. Confocal laser scanning microscope (CLSM) results prove that ATS, AT and AS possess good antibacterial adhesion properties, and the silver particles endow the emulsions with excellent bactericidal ability. Results of FT-IR and SEM show that the hydrophobic layer is formed by the cross-linking of Si—O—Si on the surface of the mortar. The new type of coating is meaningful for the service life improvement of marine concrete.