A new well-designed two-step injection solution-based method has been proposed to rapidly prepare uniform silver nanowires on a gram-scale. Uniform silver nanowires with different and controllable aspect ratios can be synthesized in high yields. Due to a high chemical reaction rate arising from high AgNO₃ concentration, the whole synthetic process of the silver nanowires is rapid and can be controlled within 20 min. The influences of different experimental parameters on the morphologies of silver nanoproducts in such a high-concentration synthesis were investigated. It was found that the addition of an appropriate amount of Cl⁻ ions had significant impact on the formation and the aspect ratios of the silver nanowires. Solution volume effect was also studied. It was shown that our synthetic method strongly favours the synthesis of silver nanowires in large solution volumes. A reasonable formation mechanism of the silver nanowires was put forward based on novel experimental phenomena. The mutual attachment of silver nanowires was observed and was found to play an important role in such high-concentration synthesis of silver nanowires. This facile scalable preparation method of silver nanowires can decrease the synthetic cost greatly and broaden the research and application areas of silver nanowires.