The academic circle thinks that Maowusu area was not desertized before Song Dynaty according to the existence of many urban ruins of Han Dynasty and Tongwan city in Maowusu area This article thinks that these special archaeological ruins with military nature can’t be the base to reflect whether the environment in the area is good or bad It thinks that the year when the area was desertized dates back to Xia Dynasty,the question is proved by historic documents and the bases provided by the geology in the Quaternary Period It points out that there are desert period and interval desert in Maowusu area because of the constraint of the environmental factors like climate Before Qin and Han Dynasty, because the human action to the nature was very limited which made the equilibrium relationship between the human beings and the nature coordinated The damage of the ecological balance in the desert period will be gradually recovered in the interval desert period The development and migration in Qin and Han Dynasty cost hundreds of thousands of yuan,which made the weak environment in the area unbearable and the damage in the desert period could not be recovered,which made it ineviable that Maowusu was desertized and the adverse environmental factors led to the complete desertization of Maowusu
