This study was carried out to investigate euphausiid abundance in an acoustic survey from March 2010 to July 2010 to suggest reasonable usage and management of the euphausiid Euphausia pacifica in the coastal area of Guryongpo Pohang. The acoustic data were analyzed by the 2-frequency difference method and the distorted wave born approximation acoustical theoretical model, which is used for organisms of weak target strength with small scatter, such as euphausiid scatter, among other marine organisms. The distribution and monthly density of euphausiids were estimated in the survey area. The results show that the volume back scattering strength frequency difference for euphausiid was 13.91-7.6 dB, and their monthly averag density was 28.2 g/m2.