Abstract:In the paper, we describe in detail the observation principle, then introduce the design of a new model AC geo-electrical resistivity measurement system. Finally, we show the preliminary experimental results, carried out in Jiangning observatory, Jiangsu province. These experimental results show that AC geo-electrical resistivity observation method can decrease the electromagnetic interference caused by the environment, meeting geo-electrical resistivity observation requirements.It is proved that the AC geo-electrical resistivity observation method could obtain high signal-noise ratio when working in strong interference observation environment, especially to decrease the interference caused by subway.