Nano zero-valent iron prepared from Marjoram (Mar-nZVI) and nano zero-valent iron prepared from Moringa (Mor-nZVI), with and without Helianthus annuus L. for the removal of thiamethoxam pesticide from soil has been investigated. Structure and morphology of Mar-nZVI and Mor-nZVI, were characterized by UV spectroscopy and High-resolution transmission electron microscopy (HRTEM). The results showed that the Mar-nZVI played the most important role in the removal of thiamethoxam in the soil, compared with natural degradation in soil without nZVI. The percent removal of thiamethoxam in the soil by Mar-nZVI and Mor-nZVI reached 75.13 and 66.83%respectively, compared with 61.06% in soil without nZVI through 12days. Thiamethoxam was removed more quickly in the presence of H. annuus plus nZVI than that by H. annuus alone. Thiamethoxam uptake into the H. annuus roots at high level and reached the maximum 17.35 µg/g after 6 days of exposure. While, in H. annuus roots treated with Mar- FeNps and Mor- FeNps reached 9.51 and 11.60 µg/g, respectively. The accumulation of thiamethoxam in H. annuus leaves were lower efficient under the treatments of H. annuus L. plus nZVI than that by H. annuus alone. This is attributed to the role of nZVI alone in degradation of thiamethoxam in soil. Therefore, the concentration of thiamethoxam was more decreased in the roots and in the leaves of H. annuus Conclusively, from these results it be concluded that helianthus annuus L. plus nZVI plays a major role for the remediation of thiamethoxam-contaminated soil. Keywords: Thiamethoxam, green nanotechnology, phytoremediation, soil.