Au nanorods with a low toxicity are important in medical field. The nanorods are generally fabricated by using cetyltrimethylammonium bromide (CTAB), which has a high toxicity. We have attempted the fabrication of Au nanorods without CTAB reagent. In this study, Au nanoparticles as growth seeds of the nanorods have been fabricated by using Au rods and NaCl aqueous solution. Subsequently, Au3+ ions of HAuCl4 have been reduced in the mixing solution, which includes the Au nanoparticles and the NaCl aqueous solution, by means of the solution plasma between W rods. The amount of Au3+ ion has been directly monitored during the solution plasma process by using in‐situ UV–Vis‐NIR. The fabricated solution possesses the Au nanoparticles of shapes of rod, sphere, triangle plate and hexagonal plate, respectively. The Au nanorods may be fabricated by both aggregating the reduced Au3+ ion at the surfaces of the Au nanoparticles as the growth seeds and controlling the growth orientation of the Au nanorods by the adsorption of Cl− ions on Au{100} facets. To control the narrow dispersion relation between the short and the long axes lengths of the Au nanorods, the addition of HAuCl4 aqueous solution in small volume steps is a key point. Copyright © 2016 John Wiley & Sons, Ltd.