A method for cleanly producing organic bismuth catalyst bismuth iso-octoate belongs to the technical field of preparation of catalysts. Bismuth iso-octoate is prepared via two-step reaction by using bismuth oxide, acetic anhydride and iso-octanoic acid as main materials and acetic acid as a solvent, the structure of the bismuth iso-octoate is characterized by using infrared spectrum (FT-IR), and the content of metal ion bismuth in bismuth iso-octoate is measured by using EDTA (ethylenediaminetetraacetic acid) complexometry. The materials are easy to obtain, the price is low, the solvent is reusable, no three wastes are produced, and the prepared bismuth iso-octoate may act as a novel efficient nontoxic green polyurethane elastomer catalyst to replace currently used organic heavy metal catalysts of tin, lead and mercury having great toxicity.