Abstract: In the paper,Wuliangsuhai lake,located in the arid area of North China,is taken as a case,in consideration of the characteristics of the shallow depth in the arid area.Through the relative analysis of one,two and three times' real-measured depth data and the reflectance of satellite images,the water depth is estimated based on the logarithm or non-logarithm model of five-,three-,two- and one-variable using the Landsat TM/% ETM data and the real-measured depth data from 2002 to 2004 according to the principle of water depth remote sensing.By model comparison and error analysis,the non-logarithm model of five-variable with three-time mesured data is selected as the optimal depth model.The model uses the multi-spectral composition method to estimate water depth,solving the problem that the single spectral can not reflect the spatial changes of submerged weeds,reeds,water color and bottom matter.The model accords with the characteristics of shallow lake in the arid area and can provide the new approach and reference for the other lakes of the arid area.