In this paper, silver nanostructures were synthesized via a solvothermal method by reducing silver nitrate with ethylene glycol in the presence of poly (vinylpyrrolidone) and using NaCl, MgCl2, AlCl3, FeCl3, Fe2(SO4)3 , NaOH, NaBr and Na2S as reaction inhibitor, respectively. Characteristics of the as-prepared silver nanostructures were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-visible (UV-vis) absorption spectrum. It is found that the mixture of nanoparticles and nanorods and nanowires can be observed in the AlCl3 and NaOH systems, the nanorods as main products can be obtained in the MgCl2 and NaCl and Fe2(SO4)3 systems, the large scale silver nanowires as main products can be obtained in the FeCl3 and Na2S systems, especially in the Na2S system, silver nanowires are very long and curved. The results indicated the reasons of the effect of the reaction inhibitors on the morphologies of silver nanostructures depend on the solubility product constant of silver salt which formed with silver ion and inhibitor anion ion in the initial stage and the properties of metal cationic ion of inhibitor. The smaller solubility product constant of silver salt or the presence of Fe3+ or low valence metal ion greatly facilitate the formation of one-dimensional silver nanostructures, especially to nanowires.