The purpose of this article is to study the effect on the healing of immediate replanted teeth after the biological characters of roots were changed by using exogenous fibronectin (Fn). Two adult rhesus monkeys were chosen in the experiment. Upper-incisors of each monkey were extracted. The teeth of experimental group were extracted the roots treated by 0.5 mg/ml Fn solution and replanted immediately. The roots of another animal were used as controls. After operations, the experimental specimens of 4 weeks and 8 weeks were examed histologically by light microscope and studied quantitatively by computer image analysis system. The results reveal that Fn can enhance periodontal healing by improving periodontal reattachment and reducing root resorption of replanted tooth. Fn has also the function to reduce inflammatory reactions significantly during the healing process.