Abstract: This paper is mainly concerned with Multibeam Echo-Sounder Systems.By comparing different systems in the aspects of system performance, design theory, survey purpose, accuracy and resolution, survey efficiency as well as software functions, we chose EM950 & EM3000 to be applied for "Continental Shelf Survey" and "shallow water engineering survey".This paper describes system configuration and features of EM950 & EM3000.Through Sea Acceptance Test in April of 1998 the accuracy of two systems was proven, consistent with the technical specification provided by Kongsberg Simrad.Through field survey, this paper illustrates there are two factors (motion sensor compensation and sound velocity) mainly effect acquired data quality.