A trial to index for deep burn injuries (IDBI) on the basis of 304 burn sites in 117 patients was reported in this paper. Based on the index, a gradation of IDBI from Type I to Type V was developed. Further analysis of the 117 cases suggested that the IDBI might provide a reliable numerical indication system for the early diagnosis, guide for repair, prognosis as well as further study in the field of the deep burn injuries.