To investigate the molecular mechanisms of Qinjiao Biejia Powder in improving skin lesions and inflammatory response in mice with psoriasis.Methods:Sixty mice were randomly divided into a control group，a model group，a methotrexate group(1 mg/kg)，and low-dose，medium-dose，and high-dose Qinjiao Biejia Powder groups(0.98，1.95，and 3.90 g/kg，respectively)follow the random number table method.The control group only received hair removal，and the psoriasis mouse model was established using imiquimod in other groups.Hematoxylin-eosin(HE) staining was used to observe histopathological changes in the skin lesions.The psoriasis area and severity index(PASI) was used to assess the degree of skin lesions.Enzyme-linked immunosorbent assay(ELISA) measured serum levels of inflammatory mediators.Quantitative real-time PCR(qRT-PCR) detected mRNA expression levels of interleukin-17(IL-17)，interleukin-23(IL-23)，interleukin-22(IL-22)，interleukin-6(IL-6)，and Toll-like receptor 4(TLR4).Immunohistochemistry assessed the expression of NOD-like receptor protein 3(NLRP3)，and Western blot analyzed the expression levels of NLRP3 and proteins related to the TLR4/NF-κB pathway.Results:Compared with the model group，the methotrexate group and the low-dose，medium-dose，and high-dose Qinjiao Biejia Powder groups showed significant improvement in skin lesions，notably reduced PASI scores，and significantly decreased serum levels of inflammatory mediators，as well as the expression of NLRP3 and TLR4/NF-κB pathway-related proteins(all P<0.05).Conclusion:Qinjiao Biejia Powder can ameliorate skin lesions and inflammatory responses in mice with psoriasis，likely through the inhibition of the TLR4/NF-κB pathway and downregulation of NLRP3 expression.