A biodegradable iron-based alloy composition, a medical implant applying the iron-based alloy composition, and a manufacturing method of the medical implant are provided. The biodegradable iron-based alloy composition includes at least 98 wt % of iron and 2 wt % or less of an additional material. The additional material includes 0.1 wt %-0.8 wt % of Mn, 0.01 wt %-0.15 wt % of Mo, 0.1 wt %-0.3 wt % of Cr, 0.02 wt %-0.15 wt % of C, and 0.01 wt %-0.15 wt % of Si.