Mg-Zn-Ag alloys have been extensively studied in recent years for potential biodegradable implants due to their unique mechanical properties, biodegradability and biocompatibility. In the present study, Mg-3Zn-xAg (wt％, x = 0. 2, 0. 5 and 0. 8) alloys with single-phase crystal structure were prepared by backward extrusion at 340 ℃. The addition of Ag element into Mg-3Zn slightly influences the ultimate tensile strength and microstructure, but the elongation firstly increases from 12％ to 19. 8％ and then decreases from 19. 8％ to 9. 9％ with the increment of Ag concentration. The tensile yield strength, ultimate tensile strength and elongation of Mg-3Zn-0. 2Ag alloy reach up to 142, 234 MPa and 19. 8％, respectively, which are the best mechanical performance of Mg-Zn-Ag alloys in the present work. The extruded Mg-3Zn-0. 2Ag alloy also possesses the best corrosion behavior with the corresponding corrosion rate of 3. 2 mm/year in immersion test, which could be explained by the single-phase and uniformly distributed grain structure, and the fewer twinning.