Objective：To compare different proportions of rabbit allogeneic bone mixed with cancellous bone，cortical bone and demineralized bone matrix（DBM）in preservation of tooth extraction sites. Methods：A total of 24 New Zealand white rabbits were randomly assigned into A，B，C and D groups. The mandibular incisors were extracted on one side randomly. Group A was the blank control with tooth extraction healed naturally after treatment. Extraction sockets of group B，C，D were respectively filled with allograft bone 1（the weight ratio of cancellous bone：cortical bone：DBM=0∶9∶1），allograft bone 2（cancellous bone：cortical bone：DBM=3∶6∶1）and deproteinized bovine bone mineral（DBBM）. The morphological changes of the extraction sockets were evaluated. Micro-CT was taken 1 or 3 months after surgery to analyze the healing of sockets. The effect of different bone materials on the morphological preservation of alveolar ridge and the formation of new bone were compared. Results：The height reduction of alveolar ridge at 1 and 3 months after tooth extraction was D