Based on the geotechnical engineering investigation for the Navigation Channel Improvement Project on the Lancang-Mekong River (Phase II) about 631 km from China-Myanmar boundary tablet 243 to Luang Prabang,Laos by comprehensive means,we probe into the geotechnical engineering conditions from the geological structure topography,landform and their characteristics of rise or fall,stratum lithology and bad geological process,classify the hazardous rapids according to the geotechnical engineering conditions,conclude the geotechnical engineering conditions for bedrock hazardous rapids,estuary rushing rapids and shallow rapids,and put forward suggestions on rapids improvement from the views of geotechnical engineering.