Nucleotide-binding oligomerization domain-like receptor pyrin-domain-containing protein 3 (NLRP3) inflammasomes trigger a defense mechanism in response to physiological or pathological reactions caused by various injuries, and they have critical roles in the development of many major diseases. The development of plant source anti-inflammatory agents and the assessment of their anti-inflammatory properties still face many challenges, such as high costs and long testing periods. Exogenous anti-inflammatory factors can be evaluated at the protein level using the NLRP3-green fluorescent protein (GFP) THP-1 cell-based biosensor. To achieve this, THP-1 cells were stably transfected with a plasmid encoding the GFP reporter gene that is under the transcriptional regulation of the NLRP3 promoter. Because the NLRP3 promoter controls the green fluorescent signal, the fluorescence is an indicator of NLRP3 activity. Our results show the fluorescence intensity was dependent on both the degree of inflammation and the effect of the anti-inflammatory agent. Here, we successfully used the biosensor to screen an NLRP3 inhibitor in the presence of polyphenols. Our results demonstrate the potential of this cell-based biosensor in monitoring the development of inflammation and in screening inflammatory inhibitors.