关键词: 龟兹县, 契吴城, 诸次水, 榆林塞

Abstract: The purpose of this paper is to reapear the landscape of this area in 5th Century in order to reveal the geographical environmental changes.
In the first century B.C.(Han Dynasty) a county called Chiou-Tsy was set up in this area to arrange the great number of immigration from Chiou-Tsy area Shi-Yuh(now shin-Jiang).
In 5th century on the chih-Wu mountain (now Alatolahai hill, south-west of Dabchiak town) has build up a city Called Chih-Wu.At that time near the Chih-Wu mountain there Was a vast swamp and a river (now Tu-Wei R.), Now it becomes a desert.
At that time, on the middle reaches of Ju-Tsy river, to the north of the Great wall, there was a fortress called a ＂Yu-Lin fortress＂ with luxuriant elm trees. To the west of the fortress there were a series of swamps covered with elms and willows crossing the sand plain and reaching the northwest part of chiou-Tsy county.
There was a main route form Shia-Jou (now Bai-Cheng-Tzy Ruin) pass ing through chih-Wu city.across the Ordos platean, leading to the northern frontier of china.later of Shia-Jou was lie wastde.