The 4N-Mg alloys with and without modification and the TC4 alloy were embedded in the thigh bones of rabbits. The slices were tested by X-ray method and the concentrations of Mg2+ ion in blood were measured for the died rabbits after operation for 2, 6, and 12 w, respectively. The specimens were analyzed by SEM and EDS, and tissue slices were observed by optical microscope. The vivo results show that the magnesium concentrations in the blood of two groups of animal subjects were in the normal scale. The Mg-based materials have good bone inducement and show the better capability of bonding with bone. The new bone mineralizes obviously on the interface. And on the new bone, the osteoclast cells array orderly. The untreated magnesium-based materials are corroded faster than the treated magnesium-based materials. All results indicate that the Mg-based materials show better biocompatibility and capacity to induce new bone, and the surface modification has an effect to control the corrosion rate of Mg-based biomaterials