In this work, a series of biodegradable pure iron, Fe–30Mn and Fe–30Mn–Ag alloys were developed by using a rapid solidification technology. A fine α-Fe dendrite was formed in pure iron, resulting in a high compressive yield strength of above 300 MPa. The Fe–30Mn alloy doped with only 1% Ag exhibited a significant increase in the degradation rate in simulated body fluid due to the precipitation of Ag-rich particles in alloy matrix and the induction of the microgalvanic corrosion. In addition, the novel Fe–30Mn–Ag alloy also exhibited a good magnetic compatibility and offered a closely approaching requirement for biodegradable medical applications.