This paper mainly discusses the effect, conventional method and advantage of 3 S technology applied in exploration of sites. Because of the difficulty of general investigation, especially, some unidentified small sites in the imagery, the idea of multi-resource geo-information exploration composite, based on the knowledge of landmark spatial relationship, was put forward. Take Zhe Gao area in Chao Hu as an Example, old Channel information layer and digitized topographic map extracting from remote sensing image in this area is indicated independent of object (including known and suspected sites) layer laminated, according to distribution law in geographical information system of summarized known sites and screened out suspected sites. In the end, compare the information of GPS with recent field measured data of Chao Hu cultural relics management department, it was found that extracted suspected sites contained mass screening recorded sites, and also had obtained the best result.