Landslide investigation is the important part of geotechnical engineering investigation,and is of great significance for the prevention and treatment of landslide disasters.The comprehensive use of engineering geological surveying and mapping,drilling,geophysical prospecting,indoor test and monitoring and other technical means,as well as the combination with geological theoretical knowledge,can comprehensively identify the geological structure,material composition,hydrogeological conditions and deformation mechanism of the landslide body,and provide a reliable basis for landslide management.This paper systematically expounds the key technologies in landslide investigation and discusses the application of geological theoretical knowledge,which has reference value for guiding the practice of landslide investigation.