Water wave energy in the ocean, having the characteristics of inexhaustibility, large quantity and wide area, is one of the most prospective renewable energy sources for large-scale application. The emerging triboelectric nanogenerator (TENG) provides a more reliable method for effectively collecting low-frequency ocean wave energy. Here, a high-performance cylindrical pendulum shaped triboelectric nanogenerator (CP-TENG) with arched film structure is presented to harvest water wave energy. The CP-TENG consists of a stator and a rotator mainly and works in a sliding and freestanding mode. The introduction of arched film structure into the CP-TENG is the most innovative, which not only can increase the contact area very much compared with point contact or line contact or soft contact in previous TENGs, but also can decrease the friction force compared with the hard face-face contact in traditional rotational TENGs. Meanwhile, it can realize the two-direction motion of the rotator. The dynamic behavior of the CP-TENG is analyzed theoretically first, and then the optimization is done systematically. The experimental results indicate that the CP-TENG can effectively scavenge multi-direction vibration energy and convert it into electrical energy. When driven by a linear motor, its peak power and average power can reach 22.1 mW and 5.2 mW, respectively. Correspondingly, the peak power density and average power density is 28.2 W m−3 and 6.6 W m−3 respectively, which are 4.0 and 3.8 times of a typical ball-shell structured TENG. The demonstration shows that this high-performance CP-TENG not only can light up 2000 LEDs directly, but also power many small electronic devices. Moreover, a full-automatic hydrological monitoring and wireless data transmitting system were powered by a CP-TENG network successfully. Therefore, the CP-TENG network located in the sea surely has great application in harvesting large-scale blue energy and powering various marine sensors in the ocean in future.