The activation of nucleotide oligomerization domain-like receptor (NLR) family, pyrin domain-containing protein 3 (NLRP3) inflammasome is implicated in the pathogenesis of various inflammatory diseases. The natural product oridonin possesses a novel mechanism for NLRP3 inhibition and a unique binding mode with NLRP3, but its poor anti-inflammatory activity limits further application. After virtual screening of diverse natural product libraries, dehydrocostus lactone (DCL) was considered as a potential NLRP3 inhibitor. DCL effectively inhibited caspase-1 cleavage and release of IL-1β in mouse and human macrophages at an extremely low concentration of 10 nM, comparable to MCC950. Mechanistically, our study assigned DCL a novel role in disrupting NLRP3 inflammasome assembly and ASC oligomerization. Excluding the influence on potassium/chloride ion efflux, calcium ion influx, and production of mitochondrial ROS, DCL formed a covalent bond with cysteine 280 in NACHT domain of NLRP3, thereby inhibiting the interaction between NLRP3 and NEK7. Furthermore, DCL exhibited protective effects in mouse models of NLRP3 inflammasome-mediated diseases, including dextran sulfate sodium-induced colitis, 2,4,6-trinitrobenzenesulfonic acid-induced Crohn's disease, LPS-induced septic shock, and monosodium urate-induced peritonitis. Our findings identify NLRP3 as the direct target of DCL, positioning DCL as a promising lead compound for treatment of NLRP3 inflammasome-related diseases.