Abstract: Based on geological data on Cangshan-Nishan fault, using field seismogeology investigation, typical geological section and coastean section analysis, this paper studies the activity characteristic, latest activity and paleo-earthquake of the Cangshan-Nishan fault.The study shows that, the Cangshan-Nishan fault is a left-strike-slip thrust fault, the activity of which shows sectional feature since late period of Quaternary. With Ganlin as a boundary, the fault can be divided into two subsections, its north-west subsection is from late period of Pleistocene to early period of Holocene, while its south-east subsection is late period of late Pleistocene;there are two paleo-earthquakes occurred on the fault about E6.4 ten thousand years(E₁) and 1.4 ten thousand years(E₂);according to textual research, the 179 BC "Qi-Chu earthquake" also occurred on this fault.According to research result of historical seismic activity and modern seismic activity, the fault is at risk of an earthquake of magnitude about 6.5 in the future.