Silver nanowires with different aspect ratios were prepared by adjusting the molar content of polyvinylpyrrolidone (PVP) through the liquid-phase reduction method. X-ray diffractometer, scanning electron microscope, UV-Vis spectrophotometer, simultaneous thermal analyzer, and transmission electron microscope were used to characterize the phase composition, microstructure, light absorption properties, thermal decomposition, and crystal structures of the silver nanowires, and the molecular dynamics was used to simulate the stretching and melting processes of single-crystal silver nanowires. Result shows that the silver nanowires are mainly composed of face-centered cubic silver. When the molar ratio of PVP to AgNO₃ changes from 1.5 to 7.5, the diameter of silver nanowires firstly decreases and then increases, and the minimum diameter of nanowires is 77.7 nm when the molar ratio is 6.0. With decreasing the diameter of silver nanowires from 106.1 nm to 77.7 nm, the melting temperature is decreased, and the lowest melting temperature is 281.2 °C. The yield strength is gradually increased from 0.63 GPa to 0.83 GPa with increasing the aspect ratios of silver nanowires from 6 to 72. The melting temperature of single-crystal silver nanowires is decreased from 690 K to 657 K with increasing the aspect ratio. Therefore, the molar ratio of 6.0 is the optimal condition to synthesize silver nanowires, and the silver nanowires with a large aspect ratio have good resistance to deformation.