Abstract: Hypack is a navigation and position system for marine survey, which supports many hydrographic survey devices. It is necessary to extract useful data for marine engineering survey from the logged raw data file. The paper discusses the raw data structure of Hypack and develops a software to process the data of raw file based on VISUAL C++ 6.0. Especially, the position data and sounding data are extracted. The software also can build a visual graph for the processed data and transform the graph into DXF format.