Photodamage, a type of skin inflammation caused by excessive exposure to solar radiation, leads to skin redness, inflammation, and even the development of skin cancer, posing a severe threat to individuals living at high altitudes. UVB radiation is considered the primary factor contributing to photodamage. It stimulates macrophages within the epidermis, triggers inflammasome activation, and increases the inflammatory cytokine interleukin-1β (IL-1β) production. This study examined the protective effects of the compound isolicoflavonol (ILF) and its mechanism against UVB-induced photodamage. We irradiated UVB to create a photodamage model in mice and macrophages. Next, we assessed ILF's ability to protect the skin and cells from UVB photodamage and its inhibitory effects on UVB-mediated NLRP3 inflammasome. Our findings indicated that ILF reduced UVB-induced skin injury and inflammation in mouse skin, decreased cell death, NLRP3 inflammasome activation, ROS production, and mitochondrial dysfunction. These results suggest that ILF may be a potent agent for protecting the skin against UVB-induced photodamage.