The topographic survey of river channels is a prerequisite for river channel navigation，flood discharge and river channel regulation，and river channel engineering construction. The existing topographic survey technologies for river channels have low operation efficiency，and operators usually face risks for wading. In view of these problems，this paper studies a section of the Jialing River in Zhaohua District，Guangyuan City，Sichuan Province，which has a length of about 2.6 km，and uses a river channel mapping technology that combines unmanned aerial vehicles（UAVs） and unmanned ships to obtain a digital orthophoto image（DOM），digital elevation model（DEM），and digital line graphic（DLG） of the test area，which all meet specifications. The results show that under the GPS-RTK inspection mode，the proportion of errors less than 0.055 m in the 1：2 000 DLG results produced by the mapping technology based on UAVs and unmanned ships accounts for 99.4% in terms of onshore topography checkpoints，and that of errors less than 0.25 m accounts for 98.4% in terms of underwater topography checkpoints，which both meet the mapping accuracy requirements of JTS 131—2012 Specifications for Port and Waterway Engineering Survey.