Abstract: Objective To study the role of apoptosis-associated speck-like protein (ASC) and caspase-1 in pathogenesis of psoriasis vulgaris. Methods Expression and distribution of ASC and caspase-1 in 30 psoriasis vulgaris patients were detected by immunohistochemistry. Results The ASC was intensely stained and expressed in cytoplasm and nuclei of psoriasis vulgaris patients and mainly expressed in middle and lower epidermis of normal persons. The caspase-1 was weakly stained and expressed in cytoplasm and full epidermis of psoriasis vulgaris patients and in basal and lower spinous cells of normal persons(t=49, 55, respectively, P< 0.01). Conclusion ASC and caspase-1 play a significant role in the inflammation of psoriasis vulgarpsoriasis.