Abstract: Algong-Teshan fault is located in the Northeast seismic area with relatively weak seismicity and relatively less research. The southern segment of the fault is the eastern boundary of Hulun Lake, and the fault scarps are developed. The linearity of the satellite image is clear, but after the northern part enters the grassland landform, the fault characteristics are almost invisible. In view of this kind of fault with no obvious features on the surface and thick overburden, the geophysical prospecting method of high-density resistivity method is adopted to measure. The survey lines are arranged in the area where the fault is speculated to pass, three high-quality sections are obtained, and the geological interpretation of the sections is carried out. The results show that the Algong-Teshan fault is NE trending and NW tending, and it is a Holocene Active fault.