Psoriasis is a refractory skin disease that seriously affects the physical and mental health of patients. It is easy to relapse and cannot be cured, which seriously harms the physical and mental health of patients. Oxidative stress, driven by increased reactive oxygen species (ROS), plays a critical role in excessive keratinocyte proliferation and local inflammation in psoriasis. In this study, we successfully synthesized a tungsten-rosmarinic acid nanoenzyme (WRA-PEG), which demonstrates promising therapeutic potential for psoriasis. Our findings demonstrate that WRA-PEG effectively scavenges ROS, reduces the proliferation of keratinocytes, and mitigates the release of pro-inflammatory cytokines in vitro. In a psoriasis-like mouse model induced by imiquimod (IMQ), WRA-PEG significantly improved clinical manifestations and prevented recurrence, as evidenced by reduced epidermal thickness and inhibited inflammatory cytokine expression, outperforming traditional treatments like Benvitimod. Bioinformatics analysis revealed the modulation of key inflammatory and oxidative stress-related pathways, highlighting the involvement of crucial genes such as CCL20 and TNFSF10 in its mechanism of action. Furthermore, WRA-PEG exhibited excellent biocompatibility and stability without adverse effects on liver or kidney function. These results underscore the potential of WRA-PEG as a novel therapeutic strategy for managing psoriasis.