The effects of Ag addition on the microstructures and mechanical properties of 7050 Al alloy were investigated. Various homogenizing and aging treatments were carried out to analyze the controversial effects of Ag in 7050 Al alloy. Transmission electron microscopy(TEM) was used for microstructural analysis. The hardening precipitates(${eta}^{prime}$) become finer with Ag addition. It suggests that Ag promotes easier nucleation of ${eta}{prime}$. The strength of overaged Ag bearing alloys are higher than that of Ag free alloy. Hardening precipitates(${eta}^{prime}$) in Ag bearing alloys are smaller than that of Ag free alloys, because the growth rate of ${eta}^{prime}$ during overaging stage is lower in Ag bearing alloys.