Abstract: Viscose-based activated carbon fiber (ACF) has characteristics such as a large specific surface area, low mass, and excellent biocompatibility, and it has good development prospects in the medical field. However, the antibacterial performance of pure ACF is limited, and surface modification methods are required to broaden its application scope in the medical field. In this paper, the hydrothermal synthesis method was used to in-situ generate ZnO on the surface of activated carbon fiber felt (ACC). By adjusting the solution concentration and hydrothermal time, the ZnO-ACF material with good antibacterial performance was prepared. The material was tested by scanning electron microscopy, infrared spectroscopy, X-ray photoelectron spectroscopy (XPS), and antibacterial and antibacterial durability tests. The results show that ZnO-ACF has good antibacterial performance. In the experiment of co-culturing ZnO-ACF with Escherichia coli, its optimal antibacterial rate can reach 99.99%, and the effective antibacterial duration can reach 4 hours. The ZnO-ACF prepared in this paper has high antibacterial activity and broad application prospects in the medical field.