The development and utilization of marine blue energy has become the focus of current research. A drawstring triboelectric nanogenerator with modular electrodes (DS-TENG) is proposed to harvest wave energy. Motion displacement and water wave adaptability are improved by using the drawstring structure in the DS-TENG. Furthermore, the modular electrode design is applied to improve the durability and replaceability of the generation units. The rationality of the structure is verified by theoretical analysis, and performance experiments on the fundamental output, displacement and frequency, durability and application are carried out. The DS-TENG can achieve output performance of 98.03 nC, 3.63 μA, 238.50 V and 923.92 µW at 150 mm and 1.0 Hz. In addition, the performance drops by 6.11% after 110,000 cycles for DS-TENG durability. This paper will provide reference for the design of TENG that adapts to a wide range of wave heights.