Abstract: Objective To observe the expressions of apoptosis-associated speck (ASC)-like protein and caspase-1 in BALB/C mice following ultraviolet B (UVB)-induced acute light injury of skin and its possible mechanism. Methods Ten BALB/C mice were divided into five groups (2 in each group). Their ears were exposed to UVB irradiation at the doses of 30, 90, 150, 300, 600 mJ/cm², respectively. The minimal erythema dose (MED) was measured. Twenty BALB/C mice were randomly divided into blank control group and experimental group (irradiated by 4 MED of UVB). Clinical and pathological changes of ear skin were compared between the two groups. Expressions of ASC-like protein and caspase-1 in ear skin were detected with immunohistochemical staining. Results Erythema, edema, telangiectasia, karyopyknosis, and perivascular lymphocytes infiltration occurred in experimental group but not in blank control group. Immunohistochemical staining showed that the expression levels of ASC-like protein and caspase-1 were significantly higher in experimental group than in blank control group (t=65.0 and 56.5, P< 0.01). Conclusion ASC-like protein and caspase-1 are expressed in BALB/C mice following UVB-induced acute light injury.