Abstract: The proper form of the internal stent for the reconstruction of the large mandibular defect was neglected for a long time.This influenced the outcome of the operation.We designed a kind of stent according to the measurement of the mandible and the requirements for restoration of the function of it.The chief point is that the position of the stent should be at the middle part between the mandibular inferior border arch and the alvelar arch.We called it an“internal interarches stent”.We used it clinieally with very good outcome.