Due to the advantages of simple structure and flexibility for energy harvesting, the tube liquid–solid triboelectric nanogenerator (TLS-TENG) has attracted much attention. However, TLS-TENG is limited by low output power due to its low surface charge density and transfer efficiency. Herein, the space volume effect is proposed in TLS-TENG, and the space volume effect TLS-TENG (SVE-TLS-TENG) is constructed with a great enhancement in the output performance. Through the space volume effect, the open-circuit voltage (Uoc), short-circuit current (Isc), and transfer charge (Qtc) of SVE-TLS-TENG can be improved by 3.5 times, 2.3 times, and 2 times, respectively. The SVE-TLS-TENG not only boasts high output performance for harvesting low-frequency and high-entropy motion energy, but its output displacement current can also serve as a compact signal generator for underwater wireless communication. The proposed space volume effect and constructed SVE-TLS-TENG offer new insight for the design and large-scale application of LS-TENG.