Finely divided silver micro-spheres were prepared with Arabic gum (AG) as dispersant through the chemicalreaction of AgNO3 and ascorbic acid. AG dispersive mechanisms in the preparation of silver powder are proposed inthe paper. The -COOH and -NH2 groups of AG reacted with Ag+ to form Ag+-AG complexes, followed by the nucleationof silver on AG polymer chains, which yielded silver spheres with an AG protection layer by reducing Ag+-AG complexeswith ascorbic acid. With the steric effect of AG, the prepared silver particles exhibit improved dispersibility. UV-Vis and FTIR spectra confirmed that silver particles were stabilized by AG.