Aim To investigate whether homocysteine (Hcy) upregulates the expression of tumor necrosis factor α(TNF-α) and interleukin-6 (IL-6) by inducing activation of nuclear factor kappa B (NF-κB) pathway by miR-33, promotes inflammatory lesions and exacerbates atherosclerosis (As). Methods RAW264.7-derived macrophages were induced by oxidized low-density lipoprotein (ox-LDL) as foam cells, and miR-33 mimics/miR-33 inhibitors were transfected into cells. Each group received 5.0 mmol/L of Hcy intervention; oil red “O” staining was used to determine whether the foam cell model was successfully induced; Western blot and real-time quantitative PCR was used to determine the protein and mRNA expression of NF-κB, TNF-α, IL-6; the cellular cholesterol content was analyzed by HPLC. Results The successfully induced foam cells were stained with oil red “O”, and the nuclei containing lipid droplets were stained red; compared with other group, the expression of NF-κB, TNF-α and IL-6 protein and mRNA, the intracellular cholesterol content was significantly increased in the miR-33 mimics group (P＜0.05). No difference was observed in the above indexes between blank group, miR-33 mimics-NC group and miR-33 inhibitor-NC group (P>0.05). Conclusion Hcy can upregulate the expression of TNF-α and IL-6 by inducing miR-33 to activate NF-κB pathway, increase inflammatory reaction and promote atherosclerosis (As).