The present invention relates to an eco-friendly herbicide comprising 8 to 15% by weight of soft water, 1.5 to 5% by weight of canola oil, 0.2 to 1% by weight of potassium hydroxide, 78 to 88% by weight of pelargonic acid, 0.2 to 1% by weight of sodium alginate, 0.2 to 1% by weight of citric acid and 0.1 to 1% by weight of beet juice, and the herbicide provides the effects of being harmless to the human body and not causing soil contamination while exhibiting not only weed control but also bactericidal, insecticidal and harmful bird and animal repellent functions.