The use of nanoparticles has increased significantly in domestic and industrial processes in recent years. These particles show special physical and chemical behavior due to their high surface-to-volume ratio, small size, and visual characteristics related to their size. Metal nanoparticles are widely used in the fields of biotechnology, bioassays, clinical diagnosis and treatment, food safety, and water and wastewater treatment. In the present study, copper nanoparticles were green-synthesized using the aqueous extract of Foeniculum vulgare leaf aqueous extract. The synthesized Cu NPs were characterized by analytical techniques including energy dispersive X-ray analysis (EDX), field emission scanning electron microscopy (FE-SEM), X-ray diffraction analysis (XRD), ultraviolet-visible (UV-vis) spectroscopy, and fourier transform infrared spectroscopy (FTIR). The anti-human lung cancer activity of Cu NPs was evaluated using MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The nanoparticles were formed in a spherical shape in the range size of 33.62 to 74.81 nm. In the antioxidant test, the IC50 of Foeniculum vulgare, Cu NPs, and butylated hydroxytoluene (BHT) against 2,2-diphenylpicrylhydrazyl (DPPH) free radicals were 99, 42, and 26 mu g/mL, respectively. In the cellular and molecular part of the recent study, the treated cells with Cu NPs were assessed by MTT assay for 48 h about the cytotoxicity and anti-human lung cancer properties on normal (human umbilical vein endothelial cells (HUVECs)) and lung cancer cell lines i.e., NCI-H2126, NCI-H1299, and NCI-H1437. The IC50 of Cu NPs were 108, 168, and 122 mu g/ mL against NCI-H2126, NCI-H1299, and NCI-H1437 cell lines, respectively. The viability of malignant lung cell line reduced dose-dependently in the presence of Cu NPs. The IC50 of Foeniculum vulgare leaf aqueous extract were 594, 781, and 610 mu g/mL against NCI-H2126, NCI-H1299, and NCI-H1437 cell lines, respectively.