Healing chronic diabetic wounds is challenging because of excessive reactive oxygen species (ROS) and hypoxia in the wound microenvironment. To address this issue, we propose a hydrogel wound dressing composed of polyethylene glycol (PEG) cross-linked with a biomimetic catalase, Fe-containing porphyrin (FeP) (i.e., FeP hydrogel). The immobilized FeP can serve as a catalyst for both ROS scavenging and O generation. The properties of the hydrogels were optimized by varying the composition ratios of the two constituent materials based on their mechanical properties and catalytic activity. Our cell experiments revealed that the FeP-80 hydrogel enhanced the proliferation and migration of keratinocytes and dermal fibroblasts and promoted the expression of angiogenic growth factors in keratinocytes. When tested with an diabetic chronic wound model, the FeP-80 hydrogel promoted wound healing by facilitating re-epithelialization, promoting angiogenesis, and suppressing inflammation, compared with other control groups.