A simple modification method for creating cotton fabrics with hydrophobic and antibacterial surface properties is proposed. Silicon dioxide nanoparticles were obtained and added to a mixed solution of ethanol and silver nitrate to form a composite solution, and the SiO2/Ag+ composite solution was used to modify the cotton fabric. Then, the fabric was modified by self-assembly of (3-mercaptopropyl) triethoxysilane (MPTES), and the modified fabric was completed by grafting dodecafluoroheptyl methacrylate using click chemistry technology. A scanning electron microscope (SEM), Fourier transform infrared spectrometer (FTIR), thermogravimetric/differential thermal analyzer (TG), and contact angle measuring instruments were used to characterize the surface morphology and wettability of the cotton fabric. The results showed that the modified cotton fabric had a contact angle of 114.3 ° and still had good hydrophobicity after being subjected to multiple frictions. The modified cotton fabric also showed good antibacterial properties against Escherichia coli (E. coli) in a Petri dish.