The invention provides a multi-azimuth scanning net-sounder. The net-sounder comprises a water-borne display control branch unit, an underwater branch unit, an energy converter array group, and a cable which connects the water-borne display control branch unit and the underwater branch unit. The water-borne display control branch unit comprises a control computer, a display, and a power supply. The underwater branch unit comprises a power switching system, a multi-channel signal generation system, a multi-channel transmission system, a multi-channel signal conditioning system, a signal collection and processing control system, and a receiving and transmitting change-over switch. The energy converter array group comprises an upward detection energy converter, a downward detection energy converter, a forward detection energy converter array, and a peripheral detection transmitting and receiving array. The net-sounder employs a combination of energy converter arrays which can scan different azimuths, employs a supersonic wave as a detection carrier, and can accurately measure various types of information about fish schools, fishing nets and underwater topography through combination with the advanced technology of signal processing. The net-sounder can be widely used for many application occasions, such as pelagic fishery production, marine fishery resources research, and lake and river fishing.