The invention discloses a system for measuring position of a marine seismic streamer based on one-way hydroacoustic ranging and belongs to the technical field of marine seismic survey. The system comprises a ship-borne system of a marine seismic survey ship, water surface units, underwater units, a dada cable and a power supply cable. The system adopts the position data of any three water surfaceunits, the vertical position data of an underwater unit to be measured and the distances between the three water surface units and the underwater unit to be measured to calculate the position data ofthe underwater unit to be measured; and the system uses the position data of the underwater units to obtain the positions of points of the marine seismic streamer by interpolation calculation. The system adopts the one-way hydroacoustic ranging, namely, the water surface units are only provided with acoustic wave launchers and the underwater units are only provided with acoustic wave receivers, thus increasing the operating range of the hydroacoustic ranging and reducing the interference of the acoustic wave launchers in a hydrophone group; and by adopting ranging acoustic wave signals of characteristic spectra, the recognition method of the ranging acoustic wave signals by the underwater units is simplified, and the system complexity is reduced.