This study aims to investigate the mechanism of total flavonoids of Dracocephalum moldavica L. (TFDM) against inflammatory response to myocardial ischemia-reperfusion injury through the establishment of hypoxia/re-oxygenation (H/R) model in H9C2 cells. The cell viability was measured by cell counting kit-8 (CCK-8). The lactate dehydrogenase (LDH) and creatine kinase isoenzyme (CK-MB) were detected by enzyme-linked immunosorbent assay (ELISA) kits. The level of intracellular reactive oxygen species (ROS) was detected by 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) fluorescent probe. The protein levels of nucleotide-binding oligomerization structural domain-like receptor protein 3 (NBFR3), Gasdermin D (GSDMD), Caspase-1, Toll-like receptor 4 (TLR4), phosphorylated nuclear factor κB P65 (P-NF-κB P65, p-p65), apoptosis-associated speck-like protein containing a CARD (ASC) were detected by Western blot. The NLRP3 agonist BMS-986299 was used to further validate the inhibitory effect of TFDM on inflammatory responses. The results showed that TFDM significantly increased the activity of H9C2 cells and decreased the expression levels of LDH, CK-MB and ROS. TFDM decreased the expression levels of NLRP3, GSDMD, Caspase-1, TLR4, p-p65, ASC. The above findings demonstrate that TFDM may improve the inflammatory response to myocardial ischemia-reperfusion injury by inhibiting the activation of NLRP3 inflammatory vesicles, and the mechanism may be related to the down-regulation of the TLR4/NF-κB signaling pathway.