Calcium alginate fiber has become an ideal raw material for wound dressing preparation due to its excellent moisture absorption and biological compatibility. There are still some problems such as bacterial contamination of wounds and difficult observation of wound healing in the actual use process. To avoid bacterial contamination of the wound and visually observe the wound healing situation, a calcium alginate fiber with pH‐responsive and antibacterial properties has been developed by the facile and eco‐friendly one‐step method. In order to make the calcium alginate fiber can be used intelligently to continuously monitor wound changeable pH, the fiber is originally solution dyed by alizarin dye. And the antibacterial property of this calcium alginate fiber is mainly from silver nanoparticles (AgNPs) which are in situ reduced by alginate in the spinning solution. This one‐step wet spinning method can avoid the subsequent complicated process required for calcium alginate fiber functionalization while ensuring the material properties. Owing to the existence of AgNPs, the calcium alginate fiber prepared has a significant antibacterial effect on two kinds of gram bacteria. Therefore, this calcium alginate fiber exhibits good pH‐responsive and antibacterial properties performance and is an improvement upon the current flexible pH sensor to indicate wound healing.