Method of displaying underwater detection image and underwater detection device

An underwater detection device in which an ultrasonic signal having a predetermined beam width is periodically transmitted underwater, and receives a signal reflected on a detection target object moving underwater, generates information on the detection target object based on the received signal, and displays the information on a display module, comprising:

• a detection module for periodically detecting the detection target object and a position thereof based on the received signal;
• a coupling module for coupling the same detection target objects by associating the same based on the detection target object and the position periodically detected by the detection module;
• an image display control module for associating a displacement symbol corresponding to a change in a position of the detection target object with the detection target object coupled by the coupling module, and displaying the displacement symbol at the detected position of the detection target object at least on a two-dimensional position coordinates displayed in the display module.