By adjusting sputter current from 1.3 A to 2.0 A in reactive magnetron sputtering deposition processes, Ag doped amorphous carbon films (a-C:Ag) with doping content from 0.7at% to 41.4at% were prepared. The influence of Ag content on structure, component, mechanical and electrical properties of a-C:Ag films were systematically studied. The results showed that Ag atoms were dissolved in amorphous carbon matrix at low Ag content (0.7at% to 1.2at%) conditions. However, Ag nanocrystal with a size around 6 nm formed when Ag content increased to 13.0at%. With the increase of Ag content, the size of sp ² clusters in the amorphous carbon matrix increased while the structural disorder degree decreased. Stress test indicated that in the low Ag content range, Ag atoms were dissolved in carbon matrix which played a pivotal role in promoting relaxation of bond length and angle distortion, thereby the film stress was reduced. Ag atoms started to form Ag nanocrystals as the Ag content increased. As a result, film stress would be reduced due to release of excessive distortion by sliding and diffusion at the grain boundaries. When Ag content reached 37.8at%, a-C:Ag exhibited transition from metal to semiconductor characteristic near 11.6 K. However, as the Ag content increased to 41.4at%, the films displayed semiconducting characteristics in the whole test temperature range (2-400 K) and exhibited typical thermal activation mechanism within temperature range of 164-400 K.