Contact-electrification (CE) is not limited to solid–solid cases, but also occurs at the liquid–solid interface. The charge transfer phenomenon between liquid and solid was widely studied by advanced technologies, such as KPFM, and has shown that electron transfer and ion transfer are both involved in liquid–solid situations. Building on recent years’ understanding of the fundamentals of liquid–solid CE, the applications of triboelectric nanogenerator (TENG) based on CE between liquid and solid range from water energy harvesting to sensing systems, and TENG probes are developed. In this chapter, recent advancements in the applications of TENGs utilizing liquid–solid CE are introduced in detail, the application mainly focuses on their roles as energy harvesters, sensors, and TENG probes, which can realize liquid kinetic energy converted into electricity, self-powered microfluidic or chemical sensing, and the liquid–solid interfaces intensive study. For energy harvesting, the liquid droplet-based TENGs are highlighted in detail, and a maximum charge density of 5.4 mC m−2 is achieved with an individual droplet. During the application of sensing using liquid–solid CE, the demonstration of detecting or monitoring liquid motion, mechanical vibration, ion concentration, sediment, and wave state is presented. As for a probe, the studies of chemical analysis in liquids, fluid status monitoring, and taste-sensing are discussed in detail. At last, some perspectives on the future development of this research direction are presented.