Ocean exploration and underwater monitoring are becoming increasingly vital due to the abundant biological, mineral, energy, and other resources in the ocean. In this paper, a triboelectric nanogenerator (TENG) based on laser processing technology is proposed for underwater monitoring of mechanical motion/triggering as well as signal screening. A self-powered wave sensing unit with a stable electrical output is fabricated by means of a new performance enhancement method for dielectric friction materials combined with an external flexible waterproof encapsulated housing. The unit can accurately respond to a variety of external mechanical stimuli. More precisely, it can analyze three basic elements of waves: frequency, amplitude and waveform. We construct a wave equivalent testing platform and perform equivalent wave tests on the sensing unit to realize sensing and analysis of wave information. We also explore the response time of the sensing unit to changes in the wave conditions. The developed self-powered sensing unit based on the TENG technology is not only low-cost and has a simple structure, but is also accurate and stable. Finally, the proposed work provides new ideas for future seabed exploration and ocean monitoring.