The Lancang-Mekong River channel phase II remediation project is 631 km in length，which is characterized by large drop，rapid water flow，large flow velocity，and complicated water regime. Multiple devices and technologies are used for segment management and implementation in hydrographic survey，such as the slop survey，the hydrological section survey and the surface velocity and flow direction surrey ect., among which，the electronic buoy method has a good effect on the measurements of the surface flow velocity and flow direction of a river section with a large flow velocity，thus it may serve as reference for the hydrological survey of long-distance mountainous river channel regulation.