This paper presents the importance of urban soil and water conservation, based on which it mainly introduces the applications of visualization technology in Haidian region of Beijing. During this course, the methodology we used is as follows: first by measuring and investigating the whole area(15.6 km~2), we obtained statistical data needed, and then on the basis of analyzing the aerial photographs(taken in 1999) of part of the region(about 8 km~2), by utilizing Virtuozo NT, Imagis, Cybercity etc., we measured and estimated the strength of soil and water loss in part of the region, and gave birth to some 3D simulated-maps. According to our incomplete investigation, (1) there are as many as 47 mainreal-estate developers, of which the constructive area comes to (211.406 7) hm~2, causing about 163.074 5 hm~2 land bare, (2) and 6 road-constructed projects added up to 8 675 m, causing another 4.223 9 hm~2 land bare. On the whole, there are 191.566 2 hm~2 bare land, which accounts for 12.28% of the whole investigated area. The results show that (1) the soil and water loss of Haidian region is chiefly caused by human activities, (2) solid waste produced by production affects more conspicuously than daily life actions, and (3) real-estate developing is the key reason for this loss.