The utility model discloses a bone interior prefilling device used in centrum kyphosis forming surgery. The bone interior prefilling device comprises sponge particles for prefilling and a pushing and plugging mechanism for pushing the sponge particles. Medical III type sponge is adopted in the sponge particles, and the sponge particles are uniform balls with the diameter of 4.0 mm to 5.0 mm when not compressed. The pushing and plugging mechanism comprises a working sleeve and a push rod plugged in the working sleeve, and the diameter of an inner hole of the working sleeve is larger than or equal to 2.5 mm but smaller than or equal to 3 mm. The compressed sponge particles plugged in the working sleeve are pushed into a working space established by a centrum interior ball through the push rod, and the sponge particles recover into the original size under the condition that the space is not externally pressed. In the bone cement injection process, the purposes of absorbing residual water in the bone cement and decreasing the bone cement flow speed can be achieved, the seepage probability of the bone cement is reduced, and the surgery safety is improved.