An iron-based alloy absorbable and implantable medical device for internal fixation. A substrate includes an iron-based alloy and degradable polymer. The mass ratio of the iron-based alloy to the degradable polymer is between 1:4 and 4:1. The weight-average molecular weight of the degradable polymer is between 150000 to 3000000, and the polydispersity index thereof is between 1 and 6. The device further includes antioxidants. The iron-based alloy is used as a load-bearing framework or reinforcement phase of the device. By adjusting the mass ratio of the iron-based alloy to the degradable polymer and the combination mode thereof, the corrosion rate of the iron-based alloy in the late period of the implantation is accelerated, and the quantity of corrosion products poorly soluble in the iron-based alloy is reduced. Adding antioxidants to the device further reduces the quantity of the corrosion products poorly soluble in the iron-based alloy.