The present invention provides a method for producing silver nanoparticles by employing ethanolamine. The method of this invention can be easily operated and no organic solvent is required. Ethanolamine first reacts with copolymers of poly(styrene-co-maleic anhydride) (abbreviated as SMA) to generate polymeric polymers. The polymeric polymers then reduce silver ions to silver atoms which are dispersed in the form of silver nanoparticles. Functional groups of the polymeric polymers can chelate with silver ions and be stably compatible with water or organic solvents, whereby the silver nanoparticles can be stably dispersed without aggregation and the produced silver nanoparticles.