We evaluated the progressing period of ligature induced periodontitis in chinese minipig. Plaque index (PLI), bleeding index (BI), probing pocket depth (PD) and clinical attachment level (CAL) were measured in 3 minipigs. On weeks 4 and 8, there was a significant increase of the mean values of PD and CAL. After this active phase, there was no further destruction up to 20 weeks. Following ligature removed probing depths decreased in 3 weeks, but they did not restore to the baseline. It suggests that using ligature induced periodontitis model to evaluate the treatment therapy and medicine effect have to consider the self-healing of lesions, when a treatment trail is carried out in a model.