Aberrant activation of the NLRP3 inflammasome contributes to the onset and progression of various inflammatory diseases, making it a highly desirable drug target. In this study, we screened a series of small compounds with anti-inflammatory activities and identified a novel NLRP3 inflammasome inhibitor, AI-44, a curcumin analogue that selectively inhibited signal 2 but not signal 1 of NLRP3 inflammasome activation. We demonstrated that AI-44 bound to peroxiredoxin 1 (PRDX1) and promoted the interaction of PRDX1 with pro–Caspase-1 (CASP1), which led to the suppression of association of pro-CASP1 and ASC. Consequently, the assembly of the NLRP3 inflammasome was interrupted, and the activation of CASP1 was inhibited. Knockdown of PRDX1 significantly abrogated the inhibitory effect of AI-44 on the NLRP3 inflammasome. Importantly, AI-44 alleviated LPS-induced endotoxemia in mice via suppressing NLRP3 inflammasome activation. Taken together, our work highlighted PRDX1 as a negative regulator of NLRP3 inflammasome activation and suggested AI-44 as a promising candidate compound for the treatment of sepsis or other NLRP3 inflammasome-driven diseases.