The invention discloses a method for green synthesis of nanometer zero-valent iron suspension liquid with peels or seed kernels. Ferric ions are reduced with plant total phenols in peels or seed kernels as a reducing agent to generate the nanometer zero-valent iron suspension liquid. The method for preparing the nanometer zero-valent iron suspension liquid from total phenols comprises the steps of extracting plant total phenols from waste peels or seed kernels, introducing nitrogen to remove dissolved oxygen in total phenol solution and ferric ion solution, and ferric ions are reduced by means of the reductibility of total phenols to generate zero-valent iron. The obtained zero-valent iron suspension liquid has high dispersity and reaction activity. The preparing method is easy to operate, the synthesized material is environment-friendly, low in cost and high in effectiveness, and equipment is simple. The zero-valent iron suspension liquid is used for removing hexavalent chromium in water, the rate of removing hexavalent chromium of 20 mg/L is 93-98%, removing speed is high, removing rate is high, secondary pollution to polluted water is avoided, and the zero-valent iron suspension liquid has broad application prospects in remediation of water polluted by hexavalent chromium.