Abstract: In this paper, the overflow in the middle and lower reaches of the Hotan River in summer was monitored and analyzed using the visual interpretation, supervised classification in ENVI 4.5 and functions of localization, measurement and layer overlay of ArcGIS 9.2. The results are as follows: (1) The overflow in the middle and lower reaches of the Hotan River was very serious, and the overflow in the irrigated areas in oasis should also be paid attention to; (2) Compared with other river sections, the overflow in the marginal zone of the oasis in the middle reaches was low, the overflow area was smaller than 35 km² at 94.4% monitoring dates, and there was no overflow at 45% monitoring dates. At the intersection of the section from Keshen Mishen to the old river channel and the Hotan River, the overflow areas were all larger than 35 km² at 45% monitoring dates except that there was no overflow on August 5, 2004 and July 29, 2008. Overflow along the river section from the intersection of the old river channel and the Hotan River to Xiaota was the most serious, the overflow area was larger than 70 km² in the most cases and 111 km² in maximum; (3) There were 10 overflow sites in total in the drainage basin, in which 4 overflow sites and 1 new floodplain were distributed along the left riverbank of the Hotan River, and 4 overflow sites and 1 new floodplain were distributed along the right one; there was also a overflow site on the left riverbank of the Karakax River. The overflow sites were mainly distributed along the mainstream of the Hotan River.

Key words: MODIS, summer, overflow, floodplain, monitoring and analyzing, Hotan River