The extreme high temperature oxidation behavior of commercial pure titanium was researched by Gleeble-1500 thermal simulator. The results show that the weight gain increase continually with the increase of the oxidation temperature and the time of holding temperature. There are several oxide layers at extreme high temperature. Oxygen diffuses from the path in the cracked outer oxide layer into rather compact inner oxide layer and further into metal, which actualize the commercial pure titanium's oxidation at extreme high temperature.