NLRP3 inflammasome activation plays a critical role in inflammation and its related disorders. Herein we report a hit-to-lead effort resulting in the discovery of a novel and potent class of NLRP3 inflammasome inhibitors. Among these, the most potent lead 40 exhibited improved inhibitory potency and almost no toxicity. Further mechanistic study indicated that compound 40 inhibited the NLRP3 inflammasome activation via suppressing ROS production. More importantly, treatment with 40 showed remarkable therapeutic effects on LPS-induced sepsis and DSS-induced colitis. This study encourages further development of more potent inhibitors based on this chemical scaffold and provides a chemical tool to identify its cellular binding target.