〔Abstract〕 Objective To study the key regulatory factors for in situ liquid phase reduction of nano-silver on dopamine surface and to evaluate the antimicrobial properties of the prepared surface. Methods The dopamine-modified micro-nanoporous titanium discs were immersed in silver nitrate solution with various concentrations and pH values to prepare different nano-silver modified surfaces. The surface properties were evaluated by scanning electron microscopy, atomic emission spectrometry and static water contact angle. Antibacterial activity was evaluated by the turbidity method, coating plate method, inhibition zone and live/dead bacterial staining. Results Compared with acidic and neutral environments, alkaline environments significantly promoted the deposition of silver nanoparticles, and the deposited nano-silver were smaller in size and more evenly distributed. The quantity of silver loaded on the surface was positively correlated with the concentration of silver nitrate in the solution. The antibacterial ability of the constructed surface was greatly enhanced with the increase of pH and silver concentration. Conclusion The pH value of solution has a stronger effect on in situ reduction of nanosilver compared to the concentration of silver ions, and high pH value is conducive to the preparation of good antibacterial surface for inhibiting infection.