A green method of synthesizing silver nanoparticles (AgNPs) with corn straw acting as reducing agents was used to prepare antibacterial paper. An ammonia solution, corn straw, and soluble starch were used as the silver precursor, reducing agent, and capping agent, respectively. The optimal condition for synthesizing AgNPs was obtained by varying the reactant ratio, temperature, and reaction time. The AgNPs were characterized by ultraviolet-visible (UV-vis) spectroscopy, X-ray diffraction (XRD), spray analyzer, and transmission electron microscopy (TEM). The obtained AgNPs were almost spherical and they were redispersed well in ethanol after centrifugation. Importantly, the prepared AgNPs were better applied in preparing antibacterial paper. After careful measurements, the mechanical properties and the antibacterial ability of the antibacterial paper were good. Therefore, the method of using corn straw as a reducing agent combined with AgNPs, to prepare antibacterial paper, is feasible. This method is noteworthy because corn straw is an underutilized material.