A method of preparing a silver loaded activated carbon fiber includes the following steps. A viscose fiber is treated with a hydroxyalkyl cyclodextrin aqueous solution to obtain a hydroxyalkyl cyclodextrin loaded viscose fiber. The hydroxyalkyl cyclodextrin loaded viscose fiber is then treated with a silver salt aqueous solution to obtain a hydroxyalkyl cyclodextrin and silver salt loaded viscose fiber. The hydroxyalkylated cyclodextrin and silver salt loaded viscose fiber is heated in deionized water at 80 to 100° C. to obtain a silver loaded viscose fiber. The silver loaded viscose fiber is treated with a disodium hydrogen phosphate aqueous solution and then heated under nitrogen at 400 to 600° C. to obtain a silver loaded carbon fiber. The silver loaded carbon fiber is heated under nitrogen and water vapor at 900 to 1,200° C. to obtain the silver loaded activated carbon fiber.