This paper describes an analysis result for the extraction and elevation measurement of the gravel bar as micro-topographical feature by ALOS data for the purpose of the restoration of the past water area in the Old Juyan Lake located in the lower reaches of the Heihe of northern China. Extraction and elevation measurement of about 20 gravel bars distributed from 900 m by 926 m in study area were carried out by newly created DSM and ALOS pan-sharpened image. The verification of validity of the elevation and age identification of gravel bars was performed by field survey measurements. Moreover, presumption of the Old Juyan Lake and reconstruction of their change for past about 7400 years were carried out. Finally, the influence of climate change and human activities to the change was discussed.