The invention provides a fatty acid-based extractant for heavy metal ions, a preparation method of the extractant and an extraction method of the heavy metal ions. The preparation method comprises thefollowing steps: uniformly mixing a fatty acid and an alkaline solution, and performing a reaction to obtain the fatty acid-based heavy metal ion extractant, wherein the fatty acid is one or more selected from the group consisting of hexanoic acid, heptanoic acid, caprylic acid and nonanoic acid. In the extractant for the heavy metal ions provided by the invention, the fatty acid salt reacts withthe high-valence heavy metal ions to be extracted, the high-valence heavy metal ions are combined with fatty acid radicals, the product is dissolved into the fatty acid to form an upper phase, thus the heavy metal ions are extracted from a lower-phase water phase, separation can be realized through simple liquid separation, the operation is simple, and the removal speed is rapid.